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c++visual-c++inputcingetline

Input a null value with cin or getline()

I'm trying to make a program that outputs random numbers between 1 and 21 with a loop. To exit the loop, you've to digit 'c' or 'C' and I want to make it continue the loop by pressing only ENTER, but the cin function doesn't accept a null input. Could you help me?

The code is like this:

char input[100];
int number;
do{
   //reset the variable
   input[]=null;
   cin>>input;
   if(input){
      number=rand()%21+1;
   }
   cout>>number;
} while (input)
Solution

  • Use std::string instead of a char array, and then use std::getline() to get exactly one line.

    std::string input;
while (std::getline(std::cin, input) && input != "c" && input != "C") {
    std::cout << (rand() % 21 + 1) << '\n';
}

    As an aside, it looks like you're using using namespace std;. Don't do that.