Using strcat and strncat. : string function « Data Types « C++ Tutorial

1. C++ Tutorial
2. Data Types
3. string function

#include <iostream>
using std::cout;
using std::endl;

#include <cstring>
using std::strcat;                                     
using std::strncat;                                     

int main()
{
   char s1[ 20 ] = "123456";
   char s2[] = "abcdefghi";
   char s3[ 40 ] = "";

   strcat( s1, s2 );

   cout << s1 << "\ns2 = " << s2;

   strncat( s3, s1, 6 ); // places '\0' after last character

   cout << s1 << "\ns3 = " << s3;

   strcat( s3, s1 );
   cout << s1 << "\ns3 = " << s3 << endl;
   return 0;
}

123456abcdefghi
s2 = abcdefghi123456abcdefghi
s3 = 123456123456abcdefghi
s3 = 123456123456abcdefghi