Question

This is my code to reverse a string using std::string. But it does not work..

#include <string>
#include <iostream>
using namespace std;

main()
{
   string input;
   int i, j;
   cout << "Enter a string: ";
   getline(cin,input);

   string output;
   for(i = 0, j = input.length() - 1; i < input.length(); i++, j--)
      output[i]=input[j];

   cout << "Reversed string = " << output;
   cin.get();
}

But if we replace string output as char output[100]; it works. So std::string does not allow character assignments?

Answer 1

You have to resize output:

output.resize(input.length());

or initially set length:

string output(input.length(), ' ');

#include <string>
#include <iostream>
using namespace std;

main(){
string input;
int i,j;
cout << "Enter a string: ";
getline(cin,input);
string output(input.length(), ' '); // initially set sufficient length
for(i=0,j=input.length()-1;i<input.length();i++,j--)
output[i]=input[j];

cout << "Reversed string = " << output;
cin.get();
}

See also:
std::string