What's wrong with cin >> num1, num2?

Question

#include 
using namespace std;

int main() {
  char choice;
  int solution, num1, num2;

  cout << \"Menu\";
  cout << \"\\n========\";
  cou         


        

Answer 1

cin >> num1, num2;

This syntax is not correct for what you want. To chain, use

cin >> num1 >> num2;

If you compile with warnings you'll get notified about this by the compiler

int a{}, b{};
std::cin >> a, b;

gives the error:

warning: right operand of comma operator has no effect [-Wunused-value]
std::cin >> a, b;

The whole statement is parsed as

((std::cin >> a), b);

Which consists of two comma-separated expressions. The b in that case doesn't have any effect. If you print the variables after the std::cin line above, you will always get 0 for b