#include <stdio.h>
#define STRSIZE 10
 
void swap_string(char s1[], char s2[]){
    int i;
    char tmp;
 
    for (i = 0; i < STRSIZE; i++){
        /* 文字列 s1 と s2 の各文字を交換 */
        tmp   = s1[i];
        s1[i] = s2[i];
        s2[i] = tmp;
    }
}
 
int main(void){
    char str1[STRSIZE] = "ABC";
    char str2[STRSIZE] = "123";
 
    swap_string(str1, str2);
 
    printf("str1=%s, str2=%s\n", str1, str2);
 
    return 0;
}

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