Question

How to implement the function strrev() in C

Answer 1

#include <stdio.h>
#include <string.h>

char* strrev(char* str) {
    char *p1, *p2;

    if (!str || !*str)
        return str;

    for (p1 = str, p2 = str + strlen(str) - 1; p2 > p1; ++p1, --p2) {
        *p1 ^= *p2;
        *p2 ^= *p1;
        *p1 ^= *p2;
    }

    return str;
}

int main(void) {

    char str[16] = "c c++ java";
    
    strrev(str);

    puts(str);

    return 0;
}



/*
run:

avaj ++c c

*/

 

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Answer 2

#include <stdio.h>
#include <string.h>

char* strrev(char* str) {
    char *p1, *p2;

    if (!str || !*str)
        return str;

    for (p1 = str, p2 = str + strlen(str) - 1; p2 > p1; ++p1, --p2) {
        char tmp;
        tmp = *p2;
        *p2 = *p1;
        *p1 = tmp;
    }

    return str;
}

int main(void) {

    char str[16] = "c c++ java";
    
    strrev(str);

    puts(str);

    return 0;
}



/*
run:

avaj ++c c

*/

 

70+ SQL courses for beginners and professionals