Do While loop breaks after incorrect input?
- by Daminkz
I am trying to have a loop continue to prompt the user for an option. When I get a string of characters instead of an int, the program loops indefinitely. I have tried setting the variable result to NULL, clearing the input stream, and have enclosed in try{}catch blocks (not in this example). Can anyone explain to me why this is?
#include <iostream>
#include <vector>
#include <string>
using namespace std;
int menu(string question, vector<string> options)
{
int result;
cout << question << endl;
for(int i = 0; i < options.size(); i++)
{
cout << '[' << i << ']' << options[i] << endl;
}
bool ans = false;
do
{
cin >> result;
cin.ignore(1000, 10);
if (result < options.size() )
{
ans = true;
}
else
{
cout << "You must enter a valid option." << endl;
result = NULL;
ans = false;
}
}
while(!ans);
return result;
}
int main()
{
string menuQuestion = "Welcome to my game. What would you like to do?";
vector<string> mainMenu;
mainMenu.push_back("Play Game");
mainMenu.push_back("Load Game");
mainMenu.push_back("About");
mainMenu.push_back("Exit");
int result = menu(menuQuestion, mainMenu);
cout << "You entered: " << result << endl;
return 0;
}
