#include <iostream>
using namespace std;
int main() {

int i;
string userInput;
int index;

getline(cin, userInput);

index = userInput.length();

for(i = index; i <= 0; i--) {

cout << userInput.at(i);

}

return 0;
}

Program is generating absolutely 0 output. No errors or bugs, I just can't generate any output... Any ideas to why?

CodePudding user response：

You got the loop condition wrong

Try i >= 0 (instead of <= )

In addition, you'll want to start the index at index-1

Working example:

#include <iostream>
using namespace std;
int main() {

    int i;
    string userInput;
    int index;

    getline(cin, userInput);

    index = userInput.length();

    for(i = index-1; i >= 0; i--) {
        cout << userInput.at(i);
    }

    return 0;
}

CodePudding user response：

To avoid indexing errors, use iterators:

for (auto it = std::crbegin(userInput); it != std::crend(userInput);   it)
    std::cout << *it;
std::cout << '\n';

CodePudding user response：

#include <iostream>
#include <algorithm> //for std::reverse

int main() {

  std::string userInput;

  std::getline(std::cin, userInput);

  //Print Reverse with for
  for(int i = userInput.length()-1; i >= 0; i--) {
    std::cout << userInput.at(i);
  }

  std::cout<<std::endl;

  //Reverse userInput variable content and print
  std::reverse(userInput.begin(),userInput.end());
  std::cout<< userInput;

  return 0;
}