Can you explain more about how integer division and the modulus operator work in C++, with some examples?

Question

Ryan McCombe · Accepted Answer

In C++, when you divide two integer values using the / operator, the result is also an integer. It performs what's called integer division.

The / operator returns the quotient - which is how many times the divisor goes into the dividend, rounded down.

For example:

1#include <iostream>
2
3int main() {
4  std::cout << 7 / 3;   // Outputs 2
5  std::cout << ", ";
6  std::cout << 10 / 3;  // Outputs 3
7}

12, 3

The % operator returns the remainder after integer division. For example:

1#include <iostream>
2
3int main() {
4  // 7 / 3 has a remainder of 1
5  std::cout << 7 % 3;
6
7  std::cout << ", ";
8
9  // 10 / 3 has a remainder of 1
10  std::cout << 10 % 3;
11}

11, 1

If either the divisor or dividend is a floating point number, regular division is performed instead:

1#include <iostream>
2
3int main() {
4  std::cout << 7.0 / 3;  // Outputs 2.33333
5
6  std::cout << ", ";
7
8  std::cout << 7 / 3.0;  // Also outputs 2.33333
9}

12.33333, 2.33333

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How does integer division work in C++?

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