c 字符串反转

//
//  main.c
//  cdemo
//
//  Created by liyongkai on 2021/6/6.
//

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


//首尾交换下 数组
void reverseString1(char *des) {
    if (NULL == des) return;
    
    unsigned long len = strlen(des);
    for (int i = 0; i < len/2; i ++) {
        char temp = des[len - i - 1];
        des[len - i - 1] = des[i];
        des[i] = temp;
    }
}


//首尾交换下 指针
void reverseString2(char *des) {
    if (NULL == des) return;
    
    unsigned long len = strlen(des);

    char *start = des;
    char *end = des + len - 1;
    
    while (start < end) {
        char temp = *end;
        *end = *start;
        *start = temp;
        
        start++;
        end--;
    }
}


int main(int argc, const char * argv[]) {
    char p[] = "abcde";
    
//    reverseString1(p);
    reverseString2(p);

    
    printf("%s\n",p);
    
    return 0;
}