递归可以在一行中完成这两项任务。下面是stracat()和strcmp()的一行实现。
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/* my_strcat(dest, src) copies data of src to dest. To do so, it first reaches end of the string dest using recursive calls my_strcat(++dest, src). Once end of dest is reached, data is copied using (*dest++ = *src++)? my_strcat(dest, src). */ void my_strcat( char *dest, char *src) { (*dest)? my_strcat(++dest, src): (*dest++ = *src++)? my_strcat(dest, src): 0 ; } /* driver function to test above function */ int main() { char dest[100] = "geeksfor" ; char *src = "geeks" ; my_strcat(dest, src); printf ( " %s " , dest); getchar (); } |
与my_strcmp()相比,my_strcmp()函数简单。
/* my_strcmp(a, b) returns 0 if strings a and b are same, otherwise 1. It recursively increases a and b pointers. At any point if *a is not equal to *b then 1 is returned. If we reach end of both strings at the same time then 0 is returned. */ int my_strcmp( char *a, char *b) { return (*a == *b && *b == ' ' )? 0 : (*a == *b)? my_strcmp(++a, ++b): 1; } /* driver function to test above function */ int main() { char *a = "geeksforgeeks" ; char *b = "geeksforgeeks" ; if (my_strcmp(a, b) == 0) printf ( " String are same " ); else printf ( " String are not same " ); getchar (); return 0; } |
上述函数执行非常基本的字符串连接和字符串比较。这些函数提供的功能与标准库函数不同。
如果你发现上面的代码不正确,请写评论,或者找到更好的方法来解决同样的问题。
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