Modulo Operator (%) in C/C++ with Examples

The modulo operator, denoted by %, is an arithmetic operator. The modulo division operator produces the remainder of an integer division. 

Syntax: If x and y are integers, then the expression: 

x % y

produces the remainder when x is divided by y. 

Return Value:

• If y completely divides x, the result of the expression is 0.
• If x is not completely divisible by y, then the result will be the remainder in the range [0, y-1]
• x mod y <x/2 if x>=y and x mod y=x if x<y
• If y is 0, then division by zero is a compile-time error.

For example: Consider the following code:

C++

// Program to illustrate the
// working of modulo operator
#include <iostream>
using namespace std;

int main(void)
{

    // To store two integer values
    int x, y;

    // To store the result of
    // the modulo expression
    int result;

    x = 3;
    y = 4;
    result = x % y;
    cout << result << endl;

    result = y % x;
    cout << result << endl;

    x = 4;
    y = 2;
    result = x % y;
    cout<<result;

    return 0;
}

// This code is contributed by Mayank Tyagi

C

// Program to illustrate the
// working of modulo operator

#include <stdio.h>

int main(void)
{

    // To store two integer values
    int x, y;

    // To store the result of
    // the modulo expression
    int result;

    x = 3;
    y = 4;
    result = x % y;
    printf("%d", result);

    result = y % x;
    printf("\n%d", result);

    x = 4;
    y = 2;
    result = x % y;
    printf("\n%d", result);

    return 0;
}

Java

// Java Program to illustrate the
// working of modulo operator
import java.io.*;

class GFG {

  // Driver Code
  public static void main (String[] args)
  {

    // To store two integer values
    int x, y;

    // To store the result of
    // the modulo expression
    int result;

    x = 3;
    y = 4;
    result = x % y;
    System.out.println(result);

    result = y % x;
    System.out.println(result);

    x = 4;
    y = 2;
    result = x % y;
    System.out.println(result);
  }
}

// This code is contributed by Shubham Singh

Python3

# Python Program to illustrate the
# working of modulo operator

# To store two integer values
x = 0
y = 0

# To store the result of
# the modulo expression
result = 0

x = 3
y = 4
result = x % y
print(result)

result = y % x
print(result)

x = 4
y = 2
result = x % y
print(result)

# This code is contributed by Shubham Singh

C#

// C# Program to illustrate the
// working of modulo operator
using System;
public class GFG{

  // Driver Code
  static public void Main ()
  {

    // To store two integer values
    int x, y;

    // To store the result of
    // the modulo expression
    int result;

    x = 3;
    y = 4;
    result = x % y;
    Console.WriteLine(result);

    result = y % x;
    Console.WriteLine(result);

    x = 4;
    y = 2;
    result = x % y;
    Console.WriteLine(result);
  }
}

// This code is contributed by Shubham Singh

Javascript

<script>

// Program to illustrate the
// working of modulo operator

// To store two integer values
var x, y;

// To store the result of
// the modulo expression
var result;

x = 3;
y = 4;
result = x % y;
document.write(result +"<br>");

result = y % x;
document.write(result +"<br>");

x = 4;
y = 2;
result = x % y;
document.write(result +"<br>");

// This code is contributed by Shubham Singh
</script>

Output

3
1
0

Restrictions of the modulo operator:
The modulo operator has quite some restrictions or limitations.

The % operator cannot be applied to floating-point numbers i.e float or double. If you try to use the modulo operator with floating-point constants or variables, the compiler will produce an error:

C++

// Program to illustrate the
// working of modulo operator
#include <iostream>
using namespace std;

int main()
{

    // To store two integer values
    float x, y;

    // To store the result of
    // the modulo expression
    float result;

    x = 2.3;
    y = 1.5;
    result = x % y;
    cout << result;

    return 0;
}

// This code is contributed by Harshit Srivastava

C

// Program to illustrate the
// working of modulo operator

#include <stdio.h>

int main(void)
{

    // To store two integer values
    float x, y;

    // To store the result of
    // the modulo expression
    float result;

    x = 2.3;
    y = 1.5;
    result = x % y;
    printf("%f", result);

    return 0;
}

Java

// Java implementation of the above approach
import java.io.*;
import java.util.*;

class GFG {

    public static void main (String[] args)
    {

        // To store two integer values
        float x, y;

        // To store the result of
        // the modulo expression
        float result;

        x = 2.3;
        y = 1.5;
        result = x % y;
        System.out.println(result);
    }
}

// This code is contributed by Shubham Singh

Python3

# Program to illustrate the
# working of modulo operator

# To store two integer values
x, y = 0, 0

# To store the result of
# the modulo expression
result = 0

x = 2.3
y = 1.5
result = x % y
print(result)

# This code is contribute by Shubham Singh

C#

using System;

public class GFG{

    static public void Main ()
    {

        // To store two integer values
        float x, y;

        // To store the result of
        // the modulo expression
        float result;

        x = 2.3;
        y = 1.5;
        result = x % y;
        Console.Write(result);
    }
}

// This code is contributed by Shubham Singh

Javascript

<script>

// Program to illustrate the
// working of modulo operator

// To store two integer values
var x, y;

// To store the result of
// the modulo expression
var result;

x = 2.3;
y = 1.5;
result = x % y;
document.write(result +"<br>");

// This code is contributed by Shubham Singh
</script>

Compilation Error:

Compilation Error in C code :- prog.c: In function 'main':
prog.c:19:16: error:
 invalid operands to binary % (have 'float' and 'float')
     result = x % y;
                ^           

The sign of the result for modulo operator is machine-dependent for negative operands, as the action takes as a result of underflow or overflow. 

C++

// Program to illustrate the
// working of the modulo operator
#include <iostream>
using namespace std;

int main(void)
{

    // To store two integer values
    int x, y;

    // To store the result of
    // the modulo expression
    int result;

    x = -3;
    y = 4;
    result = x % y;
    cout << result << endl;

    x = 4;
    y = -2;
    result = x % y;
    cout << result << endl;

    x = -3;
    y = -4;
    result = x % y;
    cout << result;

    return 0;
}

// This code is contributed by Harshit Srivastava

C

// Program to illustrate the
// working of the modulo operator

#include <stdio.h>

int main(void)
{

    // To store two integer values
    int x, y;

    // To store the result of
    // the modulo expression
    int result;

    x = -3;
    y = 4;
    result = x % y;
    printf("%d", result);

    x = 4;
    y = -2;
    result = x % y;
    printf("\n%d", result);

    x = -3;
    y = -4;
    result = x % y;
    printf("\n%d", result);

    return 0;
}

Java

import java.io.*;

class GFG {
    public static void main (String[] args)
    {
        // To store two integer values
        int x, y;

        // To store the result of
        // the modulo expression
        int result;

        x = -3;
        y = 4;
        result = x % y;
        System.out.println(result);

        x = 4;
        y = -2;
        result = x % y;
        System.out.println(result);

        x = -3;
        y = -4;
        result = x % y;
        System.out.println(result);
    }
}

// This code is contributed by sarajadhav12052009

Python3

# Program to illustrate the
# working of modulo operator

# To store two integer values
x, y = 0, 0

# To store the result of
# the modulo expression
result = 0

x = -3
y = 4
result = x % y
print(result)

# This code is contribute by AbhishekASLK

C#

using System;

public class GFG{

    static public void Main ()
    {
          // To store two integer values
        int x, y;

        // To store the result of
        // the modulo expression
        int result;

        x = -3;
        y = 4;
        result = x % y;
        Console.WriteLine(result);

        x = 4;
        y = -2;
        result = x % y;
        Console.WriteLine(result);

        x = -3;
        y = -4;
        result = x % y;
        Console.WriteLine(result);
    }
}

// This code is contributed by sarajadhav12052009

Output

-3
0
-3

Note: Some compilers may show the result of the expression as 1 and other may show -1. It depends on the compiler.