Numbers and Literals

Division by Zero in C++

What happens if I divide by zero in my code? Will it crash my program or give me an error?

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Dividing by zero in C++ can lead to different behaviors depending on whether you're working with integer or floating-point numbers.

Integer Division by Zero

When you divide an integer by zero, your program will crash due to a hardware exception. This is actually good - it helps you catch errors early:

#include <iostream>
using namespace std;

int main() {
  int health{100};
  int divisor{0};

  // Program crashes here
  int result{health / divisor};  

  cout << "This line never executes";
}
Arithmetic exception: divide by zero

Floating-Point Division by Zero

Floating-point division by zero behaves differently - instead of crashing, it gives you special values:

#include <iostream>
using namespace std;

int main() {
  float health{100.0f};
  float divisor{0.0f};

  float result{health / divisor}; 
  cout << "Result: " << result << "\n";

  float negativeHealth{-100.0f};
  float negativeResult{
    negativeHealth / divisor}; 
  cout << "Negative result: "
    << negativeResult << "\n";

  float zero{0.0f};
  float undefined{zero / zero}; 
  cout << "Zero divided by zero: " << undefined;
}
Result: inf
Negative result: -inf
Zero divided by zero: nan

The program produces three special values:

  • inf (infinity) when dividing a positive number by zero
  • inf (negative infinity) when dividing a negative number by zero
  • nan (not a number) when dividing zero by zero

In real programs, you should check for division by zero before performing the operation. Here's a safer way:

#include <iostream>
using namespace std;

float safeDivide(float numerator,
                 float divisor) {
  if (divisor == 0.0f) {
    cout << "Warning: Division by zero!\n";
    return 0.0f; // Or another appropriate value
  }
  return numerator / divisor;
}

int main() {
  float health{100.0f};
  float divisor{0.0f};

  float result{safeDivide(health, divisor)};
  cout << "Result: " << result << "\n";
}
Warning: Division by zero!
Result: 0

Answers to questions are automatically generated and may not have been reviewed.

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