Use push_back() to add characters to a string : string char array « string « C++ Tutorial

1. C++ Tutorial
2. string
3. string char array

#include <iostream>
#include <string>

using namespace std;

int main()
{
  string str1("A");
  string str2("B");
  string str3("G");
  string str4;

  cout << "  str1: " << str1 << endl;
  cout << "  str2: " << str2 << endl;
  cout << "  str3: " << str3 << "\n\n";

  // Use push_back() to add characters to str4.
  for(char ch = 'A'; ch <= 'Z'; ++ch)
    str4.push_back(ch);
  cout << "str4 after calls to push_back(): " << str4 << endl;
  cout << "Size and capacity of str4 is now " << str4.size() << " " << str4.capacity() << "\n\n";

  return 0;
}