What is the error

Question

What is the error pls may I know?
#include <iostream>
using namespace std;

int main() {
char s1[10], s2[10];
cout<<"Enter string 1:";
getline(cin,s1);
cout<<"Enter string 2:";
getline(cin,s2);
cout<<strcat(s1,s2);
return 0;
}

Answer 1

First of all add cstring library because strcat function is defined in the cstring library.

Secondly, i would recommend you to use cin.getline() instead of getline().
Syntax for cin.getline() function :
cin.getline(name_of_array, size_of_array)

Answer 2

Use 'cin >> s1;' to read the string