I don't understand what's wrong with this code.

Question

#include <iostream>
using namespace std;

//Simple two number calculator
//5-function calculator

int main() {
char aj;
float a, j;

cin >> a;
cout << a;

cin >> aj;
cout << aj;

cin >> j;
cout << j;

cout << " = ";

try {
if(j=0) {
throw 44;
}
}
catch (int x) {
cout << x << " - can't divide by 0";
}

switch(aj) {

case '+':
cout << a+j;
break;

case '-':
cout << a-j;
break;

case '*':
cout << a*j;
break;

case '/':
cout << a/j;
break;

default:
cout << "Error - not an operator!";
break;

}

return 0;
}

Answer 1

char aj;
float a, j;

cin >> a;
cout << a;

cin >> aj;
cout << aj;

try {
cin >> j;
if(j == 0 && aj == '/')
throw 0;
}
catch(int x) {
cout << x << " - cannot divide by zero\n";
}

cout << j;

cout << " = ";

switch(aj) {

case '+':
cout << a+j;
break;

case '-':
cout << a-j;
break;

case '*':
cout << a*j;
break;

case '/':
cout << a/j;
break;

default:
cout << "Error - not an operator!";
}

//Corrected

Answer 2

In the try statement, you're using the assignment operator (=) instead of comparison (==). It doesn't check if j is 0, but it will set j to 0. if(x=0) always evaluates to 0 (false). So you don't catch a zero division exception, but you create one yourself by setting j to 0. For the other operations, it will return a+0, a-0 and a*0.

Answer 3

Remove the try...catch block and it will work, you can validate value of 'j' in the division case as follows:

if(j == 0) {
cout << "Invalid division operand (zero)";
}

Hth, cmiiw