使用位运算符检查数字是否为正、负或零-yiteyi-C++库

给定一个数字N，在不使用条件语句的情况下检查它是正、负还是零。例如：

null

Input : 30Output : 30 is positiveInput : -20Output : -20 is negativeInput: 0Output: 0 is zero

推荐：请尝试你的方法 {IDE} 首先，在进入解决方案之前。

符号移位n>>31将每个负数转换为-1，将每个负数转换为0。当我们做-n>>31时，如果它是一个正数，那么它会像我们做-n>>31时一样返回-1，反之亦然，当我们做一个负数时。但是当我们为0计算时，n>>31和-n>>31都返回0，所以我们得到一个公式：

1+（n>>31）–（-n>>31）

..1) 当n为负时 : 1 +(-1)-0=0 ..2) 当n为正时： 1+0-(-1)=2 ..3) 当n为0时： 1+0-0=1 所以我们知道当它是负数时返回0，当它是零时返回1，当它是正数时返回2。所以不要使用我们存储在第0个索引“负”、第1个索引“零”和第2个索引“正”的if语句，并根据它打印。

CPP

                         // CPP program to find if a number is                       
                         // positive, negative or zero using                       
                         // bit wise operators.                       
                         #include <iostream>                       
                         using                                     namespace                                     std;                       
           
                         // function to return 1 if it is zero                       
                         // returns 0 if it is negative                       
                         // returns 2 if it is positive                       
                         int                                     index(                                     int                                     i)                       
                         {                       
                                                 return                                     1 + (i >> 31) - (-i >> 31);                       
                         }                       
           
                         void                                     check(                                     int                                     n)                       
                         {                       
                                                 // string array to store all kinds of number                       
                                                 string s[] = {                                     "negative"                                     ,                                     "zero"                                     ,                                     "positive"                                     };                       
           
                                                 // function call to check the sign of number                       
                                                 int                                     val = index(n);                       
           
                                                 cout << n <<                                     " is "                                     << s[val] << endl;                       
                         }                       
           
                         // driver program to test the above function                       
                         int                                     main()                       
                         {                       
                                                 check(30);                       
                                                 check(-20);                       
                                                 check(0);                       
                                                 return                                     0;                       
                         }                       

JAVA

                         // Java program to find if a number is                       
                         // positive, negative or zero using                       
                         // bit wise operators.                       
                         class                                     GFG {                       
                                   
                                                 // function to return 1 if it is zero                       
                                                 // returns 0 if it is negative                       
                                                 // returns 2 if it is positive                       
                                                 static                                     int                                     index(                                     int                                     i)                       
                                                 {                       
                                                 return                                     1                                     + (i >>                                     31                                     ) - (-i >>                                     31                                     );                       
                                                 }                       
           
                                                 static                                     void                                     check(                                     int                                     n)                       
                                                 {                       
                                   
                                                 // string array to store all kinds                       
                                                 // of number                       
                                                 String s[] = {                                     "negative"                                     ,                                     "zero"                                     ,                       
                                                 "positive"                                     };                       
           
                                                 // function call to check the sign                       
                                                 // of number                       
                                                 int                                     val = index(n);                       
           
                                                 System.out.println(n +                                     " is "                                     + s[val]);                       
                                                 }                       
                                   
                                                 // Driver code                       
                                                 public                                     static                                     void                                     main(String[] args)                       
                                                 {                       
                                                 check(                                     30                                     );                       
                                                 check(-                                     20                                     );                       
                                                 check(                                     0                                     );                       
                                                 }                       
                         }                       
           
                         // This code is contributed by Anant Agarwal.                       

Python3

                         # Python 3 program to                       
                         # find if a number is                       
                         # positive, negative                       
                         # or zero using                       
                         # bit wise operators.                       
           
                         # function to return 1 if it is zero                       
                         # returns 0 if it is negative                       
                         # returns 2 if it is positive                       
                         def                                     index(i):                       
           
                                                 return                                     1                                     +                                     (i >>                                     31                                     )                                     -                                     (                                     -                                     i >>                                     31                                     )                       
           
           
                         def                                     check(n):                       
           
                                                 # string array to store all kinds of number                       
                                                 s                                     =                                     "negative"                                     ,                                     "zero"                                     ,                                     "positive"                       
           
                                                 # function call to check the sign of number                       
                                                 val                                     =                                     index(n)                       
           
                                                 print                                     (n,                                     "is"                                     ,s[val])                       
           
           
                         # driver program to                       
                         # test the above function                       
                         check(                                     30                                     )                       
                         check(                                     -                                     20                                     )                       
                         check(                                     0                                     )                       
                                   
                         # This code is contributed by                       
                         # Smitha Dinesh Semwal                       

C#

                         // C# program to find if a number is                       
                         // positive, negative or zero using                       
                         // bit wise operators.                       
                         using                                     System;                       
           
                         class                                     GFG {                       
                                   
                                                 // function to return 1 if it is zero                       
                                                 // returns 0 if it is negative                       
                                                 // returns 2 if it is positive                       
                                                 static                                     int                                     index(                                     int                                     i)                       
                                                 {                       
                                                 return                                     1 + (i >> 31) - (-i >> 31);                       
                                                 }                       
                                   
                                                 static                                     void                                     check(                                     int                                     n)                       
                                                 {                       
                                   
                                                 // string array to store all kinds of number                       
                                                 String []s = {                                     "negative"                                     ,                                     "zero"                                     ,                                     "positive"                                     };                       
                                   
                                                 // function call to check the sign of number                       
                                                 int                                     val = index(n);                       
                                   
                                                 Console.WriteLine(n +                                     " is "                                     + s[val]);                       
                                                 }                       
                                   
                                                 //Driver code                       
                                                 public                                     static                                     void                                     Main()                       
                                                 {                       
                                                 check(30);                       
                                                 check(-20);                       
                                                 check(0);                       
                                                 }                       
                         }                       
           
                         // This code is contributed by Anant Agarwal.                       

PHP

                         <?php                       
                         // PHP program to find if a number is                       
                         // positive, negative or zero using                       
                         // bit wise operators.                       
           
                         // function to return 1 if it is zero                       
                         // returns 0 if it is negative                       
                         // returns 2 if it is positive                       
                         function                                     index(                                     $i                                     )                       
                         {                       
                                                 return                                     1 + (                                     $i                                     >> 31) -                       
                                                 (-                                     $i                                     >> 31);                       
                         }                       
           
                         function                                     check(                                     $n                                     )                       
                         {                       
                                   
                                                 // string array to store                       
                                                 // all kinds of number                       
                                                 $s                                     =                                     array                                     (                                     "negative"                                     ,                                     "zero"                                     ,                                     "positive"                                     );                       
           
                                                 // function call to check                       
                                                 // the sign of number                       
                                                 $val                                     = index(                                     $n                                     );                       
           
                                                 echo                                     $n                                     ,                                     " is "                                     ,                                     $s                                     [                                     $val                                     ],                                     ""                                     ;                       
                         }                       
           
                                                 // Driver Code                       
                                                 check(30);                       
                                                 check(-20);                       
                                                 check(0);                       
           
                         // This code is contributed by Ajit                       
                         ?>                       

Javascript

                         <script>                       
           
                         // JavaScript program to find if a number is                       
                         // positive, negative or zero using                       
                         // bit wise operators.                       
           
                                                 // function to return 1 if it is zero                       
                                                 // returns 0 if it is negative                       
                                                 // returns 2 if it is positive                       
                                                 function                                     index(i)                       
                                                 {                       
                                                 return                                     1 + (i >> 31) - (-i >> 31);                       
                                                 }                       
                                   
                                                 function                                     check(n)                       
                                                 {                       
                                                 // string array to store all kinds of number                       
                                                 let s = [                                     "negative"                                     ,                                     "zero"                                     ,                                     "positive"                                     ];                       
                                   
                                                 // function call to check the sign of number                       
                                                 let val = index(n);                       
                                   
                                                 document.write(n +                                     " is "                                     + s[val] +                                     "<br>"                                     );                       
                                                 }                       
                                   
                         // driver program to test the above function                       
           
                                                 check(30);                       
                                                 check(-20);                       
                                                 check(0);                       
                                   
           
                         // This code is contributed by Surbhi Tyagi                       
           
                         </script>                       

输出：

30 is positive-20 is negative0 is zero

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