查找给定日期的星期几-yiteyi-C++库

编写一个函数，计算过去或将来某个特定日期的星期几。一个典型的应用是计算某人出生或其他特殊事件发生的一周中的哪一天。

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建议：请在“上解决” 实践 “首先，在讨论解决方案之前。

下面是作者建议的一个简单函数坂本、拉赫曼、基思和克雷弗计算一天。下面的函数返回0表示星期天，1表示星期一等。

Understanding the Maths:14/09/1998dd=14mm=09yyyy=1998 //non-leap yearStep 1: Informations to be remembered. Magic Number Month array. For Year: {0,3,3,6,1,4,6,2,5,0,3,5} DAY array starting from 0-6: {Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday} Century Year Value: 1600-1699 = 6      1700-1799 = 4      1800-1899 = 2      1900-1999 = 0      2000-2099 = 6..Step 2: Calculations as per the steps  Last 2 digits of the year:  98 Divide the above by 4:     24 Take the date(dd):      14 Take month value from array: 5 (for September month number 9) Take century year value:  0  ( 1998 is in the range 1900-1999 thus 0)          ----- Sum:        141  Divide the Sum by 7 and get the remainder: 141 % 7 = 1  Check the Day array starting from index 0: Day[1] = Monday**If leap year it will be the remainder-1

C++

                           /* A program to find day of a given date */                         
                           #include <bits/stdc++.h>                         
                           using                                        namespace                                        std;                         
            
                           int                                        dayofweek(                                        int                                        d,                                        int                                        m,                                        int                                        y)                         
                           {                         
                                                     static                                        int                                        t[] = { 0, 3, 2, 5, 0, 3,                         
                                                     5, 1, 4, 6, 2, 4 };                         
                                                     y -= m < 3;                         
                                                     return                                        ( y + y / 4 - y / 100 +                         
                                                     y / 400 + t[m - 1] + d) % 7;                         
                           }                         
            
                           // Driver Code                         
                           int                                        main()                         
                           {                         
                                                     int                                        day = dayofweek(30, 8, 2010);                         
                                                     cout << day;                         
            
                                                     return                                        0;                         
                           }                         
            
                           // This is code is contributed                         
                           // by rathbhupendra                         

C

                           /* A program to find day of a given date */                         
                           #include<stdio.h>                         
            
                           int                                        dayofweek(                                        int                                        d,                                        int                                        m,                                        int                                        y)                         
                           {                         
                                                     static                                        int                                        t[] = { 0, 3, 2, 5, 0, 3, 5, 1, 4, 6, 2, 4 };                         
                                                     y -= m < 3;                         
                                                     return                                        ( y + y/4 - y/100 + y/400 + t[m-1] + d) % 7;                         
                           }                         
            
                           /* Driver function to test above function */                         
                           int                                        main()                         
                           {                         
                                                     int                                        day = dayofweek(30, 8, 2010);                         
                                                     printf                                        (                                        "%d"                                        , day);                         
            
                                                     return                                        0;                         
                           }                         

JAVA

                           /*This code will return the string value and the exact date                         
                                                     * both for leap and non leap years*/                         
                           import                                        java.util.*;                         
                           class                                        FindDay {                         
                                                     static                                        int                                        dd;                         
                                                     static                                        int                                        mm;                         
                                                     static                                        int                                        yyyy;                         
                                                     FindDay(                                        int                                        dd,                                        int                                        mm,                                        int                                        yyyy)                         
                                                     {                         
                                                     this                                        .dd = dd;                         
                                                     this                                        .mm = mm;                         
                                                     this                                        .yyyy = yyyy;                         
                                                     }                         
                                                     static                                        int                                        checkLeap(                                        int                                        y)                         
                                                     {                         
                                                     if                                        ((y %                                        4                                        ==                                        0                                        && y %                                        100                                        !=                                        0                                        ) || (y %                                        400                                        ==                                        0                                        ))                         
                                                     return                                        1                                        ;                         
                                                     else                         
                                                     return                                        0                                        ;                         
                                                     }                         
                                                     static                                        void                                        calculate()                         
                                                     {                         
            
                                                     // Checking Leap year. If true then 1 else 0.                         
                                                     int                                        flag_for_leap = checkLeap(yyyy);                         
            
                                                     /*Declaring and initialising the given informations                         
                                                     * and arrays*/                         
                                                     String day[] = {                                        "Sunday"                                        ,                                        "Monday"                                        ,                                        "Tuesday"                                        ,                         
                                                     "Wednesday"                                        ,                                        "Thursday"                                        ,                                        "Friday"                                        ,                         
                                                     "Saturday"                                        };                         
                                                     int                                        m_no[] = {                                        0                                        ,                                        3                                        ,                                        3                                        ,                                        6                                        ,                                        1                                        ,                                        4                                        ,                                        6                                        ,                                        2                                        ,                                        5                                        ,                                        0                                        ,                                        3                                        ,                                        5                                        };                         
            
                                                     /*Generalised check to find any Year Value*/                         
                                                     int                                        j;                         
                                                     if                                        ((yyyy /                                        100                                        ) %                                        2                                        ==                                        0                                        ) {                         
                                                     if                                        ((yyyy /                                        100                                        ) %                                        4                                        ==                                        0                                        )                         
                                                     j =                                        6                                        ;                         
                                                     else                         
                                                     j =                                        2                                        ;                         
                                                     }                         
                                                     else                                        {                         
                                                     if                                        (((yyyy /                                        100                                        ) -                                        1                                        ) %                                        4                                        ==                                        0                                        )                         
                                                     j =                                        4                                        ;                         
                                                     else                         
                                                     j =                                        0                                        ;                         
                                                     }                         
            
                                                     /*THE FINAL FORMULA*/                         
                                                     int                                        total = (yyyy %                                        100                                        ) + ((yyyy %                                        100                                        ) /                                        4                                        ) + dd                         
                                                     + m_no[mm -                                        1                                        ] + j;                         
                                                     if                                        (flag_for_leap ==                                        1                                        ) {                         
                                                     if                                        ((total %                                        7                                        ) >                                        0                                        )                         
                                                     System.out.println(day[(total %                                        7                                        ) -                                        1                                        ]);                         
                                                     else                         
                                                     System.out.println(day[                                        6                                        ]);                         
                                                     }                         
                                                     else                         
                                                     System.out.println(day[(total %                                        7                                        )]);                         
                                                     }                         
                                                     public                                        static                                        void                                        main(String[] args)                         
                                                     {                         
                                                     Scanner sc =                                        new                                        Scanner(System.in);                         
                                                     /*Take input in string format and then convert to                         
                                                     * integer values*/                         
                                                     String date = sc.next();                         
                                                     String[] values = date.split(                                        "/"                                        );                         
                                                     new                                        FindDay(Integer.parseInt(values[                                        0                                        ]),                         
                                                     Integer.parseInt(values[                                        1                                        ]),                         
                                                     Integer.parseInt(values[                                        2                                        ]));                         
                                                     calculate();                         
                                                     }                         
                           }                         
                           /*Contributed and written by Aniket Dey*/                         

Python3

                           # Python3 program to find day                         
                           # of a given date                         
            
                           def                                        dayofweek(d, m, y):                         
                                                     t                                        =                                        [                                        0                                        ,                                        3                                        ,                                        2                                        ,                                        5                                        ,                                        0                                        ,                                        3                                        ,                         
                                                     5                                        ,                                        1                                        ,                                        4                                        ,                                        6                                        ,                                        2                                        ,                                        4                                        ]                         
                                                     y                                        -                                        =                                        m <                                        3                         
                                                     return                                        (( y                                        +                                        int                                        (y                                        /                                        4                                        )                                        -                                        int                                        (y                                        /                                        100                                        )                         
                                                     +                                        int                                        (y                                        /                                        400                                        )                                        +                                        t[m                                        -                                        1                                        ]                                        +                                        d)                                        %                                        7                                        )                         
            
                           # Driver Code                         
                           day                                        =                                        dayofweek(                                        30                                        ,                                        8                                        ,                                        2010                                        )                         
                           print                                        (day)                         
            
                           # This code is contributed by Shreyanshi Arun.                         

C#

                           // C# program to find day of a given date                         
                           using                                        System;                         
            
                           class                                        GFG {                         
                                      
                                                     static                                        int                                        dayofweek(                                        int                                        d,                                        int                                        m,                                        int                                        y)                         
                                                     {                         
                                                     int                                        []t = { 0, 3, 2, 5, 0, 3, 5,                         
                                                     1, 4, 6, 2, 4 };                         
                                                     y -= (m < 3) ? 1 : 0;                         
                                      
                                                     return                                        ( y + y/4 - y/100 + y/400                         
                                                     + t[m-1] + d) % 7;                         
                                                     }                         
                                      
                                                     // Driver Program to test above function                         
                                                     public                                        static                                        void                                        Main()                         
                                                     {                         
                                                     int                                        day = dayofweek(30, 8, 2010);                         
                                      
                                                     Console.Write(day);                         
                                                     }                         
                           }                         
            
                           // This code is contributed by Sam007.                         

PHP

                           <?php                         
                           // PHP program to find                         
                           // day of a given date                         
                           function                                        dayofweek(                                        $d                                        ,                                        $m                                        ,                                        $y                                        )                         
                           {                         
                                                     static                                        $t                                        =                                        array                                        (0, 3, 2, 5, 0, 3,                         
                                                     5, 1, 4, 6, 2, 4);                         
                                                     $y                                        -=                                        $m                                        < 3;                         
                                                     return                                        (                                        $y                                        +                                        $y                                        / 4 -                                        $y                                        / 100 +                         
                                                     $y                                        / 400 +                                        $t                                        [                                        $m                                        - 1] +                                        $d                                        ) % 7;                         
                           }                         
            
                           // Driver Code                         
                           $day                                        = dayofweek(30, 8, 2010);                         
                           echo                                        $day                                        ;                         
            
                           // This code is contributed by mits.                         
                           ?>                         

Javascript

                           <script>                         
            
                           // Javascript program to find day of a given date                         
            
                           function                                        dayofweek(d, m, y)                         
                           {                         
                                                     let t = [ 0, 3, 2, 5, 0, 3, 5, 1, 4, 6, 2, 4 ];                         
                                                     y -= (m < 3) ? 1 : 0;                         
                                                     return                                        ( y + y/4 - y/100 + y/400 + t[m-1] + d) % 7;                         
                           }                         
            
                           // Driver Code                         
            
                                                     let day = dayofweek(30, 8, 2010);                         
                                                     document.write(Math.round(day));                         
            
                           </script>                         

输出： 1（星期一）

时间复杂性： O（1）看见这有关上述功能的说明。参考资料： http://en.wikipedia.org/wiki/Determination_of_the_day_of_the_week 本文由 德拉杰·贾因 并由Geeksforgeks团队审核。如果您发现任何不正确的地方，或者您想分享有关上述主题的更多信息，请写评论

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