crashed when using for loop

[aryue1945]

Hello,

I wrote a program to reverse the character order of a string. I could do it with while loop, but it crashed when I used for loop. I know it is about "j >= 0" in the for loop, it did not crash when I used j>0 instead, but it missed the last result.....

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

int main(){
     string name;

    cout << "Enter a name: ";
    getline(cin, name);

    cout << endl;


    //for loop for reverse character order
    for (unsigned j = (name.size()-1); j >= 0; j--){
        cout << name.at(j);
    }

    cout << endl;

    //whlie loop for reverse character order
    int j = name.size()-1;
    while (j >= 0){
        cout << name.at(j);
        j--;
    }

    cout << endl;

}

[keskiverto]

unsigned foo = 0;
foo--;
if ( 0 <= foo ) cout << "oh my";

Unsigned 0-1, "-1", is a very big (positive) number. Definitely > 0. You would have an infinite loop, if string::at would not eject.

Try int

or

for (unsigned j = name.size(); 0 < j; --j ) {
  cout << name.at( j-1 );
}