如代码所示

```#include<iostream>
#include<cstring>
using namespace std;

int main(){
    char s1[300],s2[100];
    while(scanf("%s %s",&s1,&s2) != EOF){
        int len1 = strlen(s1);
        int len2 = strlen(s2);
        int n = 0;
        while(n < len2){
            s1[len1+n] = s2[n];////设置一计数器从末尾开始连接即可
            n++;
        }
        s1[len1+n] = '\0';
        cout<<s1<<endl;  
    }
}