代码:

#include<stdio.h>

int fun(char c[100], char d[100])

{

    int i, j;
    for (i = 0; c[i] != '\0'; i++);

    for (j = 0; d[j] != '\0'; j++)

    {

        c[i++] = d[j];

    }

    c[i] = '\0';
    puts(c);
    return c[100];

}

int main()

{

    char a[100];

    char b[100];

    gets_s(a);

    gets_s(b);

    fun(a, b);

    return 0;

}