#include "iostream"
#include "string.h"
using namespace std;
#define N1 10
#define N2 10
#define N 20
void str_cat(char s1[],char s2[],char s[])
{
	int i=0,j=0;
	while(s1[i])
	{
		s[i]=s1[i];
		i++;
	}
	while (s2[j])
	{
		s[i]=s2[j];
		i++;
		j++;
	}
	s[i]='\0';
}
void main(void)
{
	char str[N],str1[N1],str2[N2];
	cout<<"Please intput s1:";
	cin.getline(str1,80);
	cout<<"Please input s2:";
	cin.getline(str2,80);
	str_cat(str1,str2,str);
	cout<<str<<endl;
}