Given a number n, count all multiples of 3 and/or 5 in set of numbers from 1 to n.

Examples:

Input: n = 6 Output: 3 There are three multiples of 3 and/or 5 in {1, 2, 3, 4, 5, 6} Input: n = 16 Output: 7 There are two multiples of 7 and/or 5 in {1, 2, .. 16} The multiples are 3, 5, 6, 9, 10, 12, 15

**We strongly recommend to minimize your browser and try this yourself first.**

The value of n/3 gives us number of multiples of 3, the value of n/5 gives us number of multiples of 5. But the important point is there are may be some common multiples which are multiples of both 3 and 5. We can get such multiples by using n/15. Following is the program to find count of multiples.

## C++

`// C++ program to find count of multiples of 3 and 5 in {1, 2, 3, ..n} ` `#include <iostream> ` `using` `namespace` `std; ` ` ` `unsigned countOfMultiples(unsigned n) ` `{ ` ` ` `// Add multiples of 3 and 5. Since common multples are ` ` ` `// counted twice in n/3 + n/15, subtract common multiples ` ` ` `return` `(n/3 + n/5 - n/15); ` `} ` ` ` `// Driver program to test above function ` `int` `main() ` `{ ` ` ` `cout << countOfMultiples(6) << endl; ` ` ` `cout << countOfMultiples(16) << endl; ` ` ` `return` `0; ` `} ` |

*chevron_right*

*filter_none*

## Java

`// Java program to find count of multiples ` `// of 3 and 5 in {1, 2, 3, ..n} ` `import` `java .io.*; ` `class` `GFG { ` ` ` ` ` `static` `long` `countOfMultiples(` `long` `n) ` ` ` `{ ` ` ` ` ` `// Add multiples of 3 and 5. ` ` ` `// Since common multples are ` ` ` `// counted twice in n/3 + n/15, ` ` ` `// subtract common multiples ` ` ` `return` `(n/` `3` `+ n/` `5` `- n/` `15` `); ` ` ` `} ` ` ` ` ` `// Driver Code ` ` ` `static` `public` `void` `main (String[] args) ` ` ` `{ ` ` ` `System.out.println(countOfMultiples(` `6` `)); ` ` ` `System.out.println(countOfMultiples(` `16` `)); ` ` ` `} ` `} ` ` ` `// This code is contributed by anuj_67. ` |

*chevron_right*

*filter_none*

## Python3

`# python program to find count ` `# of multiples of 3 and 5 in ` `# {1, 2, 3, ..n} ` ` ` `def` `countOfMultiples(n): ` ` ` `# Add multiples of 3 and 5. ` ` ` `# Since common multples are ` ` ` `# counted twice in n/3 + n/15, ` ` ` `# subtract common multiples ` ` ` `return` `(` `int` `(n` `/` `3` `) ` `+` `int` `(n` `/` `5` `) ` `-` `int` `(n` `/` `15` `)); ` ` ` ` ` `# Driver program to test ` `# above function ` `print` `(countOfMultiples(` `6` `)) ` `print` `(countOfMultiples(` `16` `)) ` ` ` `# This code is contributed by Sam007. ` |

*chevron_right*

*filter_none*

## C#

`// C# program to find count of multiples ` `// of 3 and 5 in {1, 2, 3, ..n} ` `using` `System; ` ` ` `public` `class` `GFG { ` ` ` ` ` `static` `uint` `countOfMultiples(` `uint` `n) ` ` ` `{ ` ` ` `// Add multiples of 3 and 5. ` ` ` `// Since common multples are ` ` ` `// counted twice in n/3 + n/15, ` ` ` `// subtract common multiples ` ` ` `return` `(n/3 + n/5 - n/15); ` ` ` `} ` ` ` ` ` `// Driver program to test above ` ` ` `// function ` ` ` `static` `public` `void` `Main () ` ` ` `{ ` ` ` `Console.WriteLine(countOfMultiples(6)); ` ` ` ` ` `Console.WriteLine(countOfMultiples(16)) ; ` ` ` `} ` `} ` ` ` `// This code is contributed by anuj_67. ` |

*chevron_right*

*filter_none*

## PHP

`<?php ` `// PHP program to find count of ` `// multiples of 3 and 5 in ` `// {1, 2, 3, ..n} ` ` ` `function` `countOfMultiples(` `$n` `) ` `{ ` ` ` ` ` `// Add multiples of 3 and 5. ` ` ` `// Since common multples are ` ` ` `// counted twice in n/3 + n/15, ` ` ` `// subtract common multiples ` ` ` `return` `floor` `(` `floor` `(` `$n` `/ 3) + ` ` ` `floor` `(` `$n` `/ 5) - ` ` ` `floor` `(` `$n` `/ 15)); ` `} ` ` ` `// Driver Code ` `echo` `countOfMultiples(6),` `"\n"` `; ` `echo` `countOfMultiples(16); ` ` ` `// This code is contributed by nitin mittal ` `?> ` |

*chevron_right*

*filter_none*

Output:

3 7

This article is contributed by **Asif**. Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above

Attention reader! Don’t stop learning now. Get hold of all the important DSA concepts with the **DSA Self Paced Course** at a student-friendly price and become industry ready.

## Recommended Posts:

- Count digits in a factorial | Set 2
- Write a program to reverse digits of a number
- Write an Efficient Method to Check if a Number is Multiple of 3
- Write an Efficient C Program to Reverse Bits of a Number
- Minimum number of jumps to reach end
- Find minimum number to be divided to make a number a perfect square
- Find whether a given number is a power of 4 or not
- Print all combinations of points that can compose a given number
- Count of Binary Digit numbers smaller than N
- Check if a number is multiple of 5 without using / and % operators
- Count of Root to Leaf Paths consisting of at most M consecutive Nodes having value K
- Count numbers that don't contain 3
- Given a number, find the next smallest palindrome
- Count the number of possible triangles
- Select a random number from stream, with O(1) space
- Program to convert a given number to words
- Efficient program to print all prime factors of a given number
- Count numbers with same first and last digits
- Check if a number is Palindrome
- Random number generator in arbitrary probability distribution fashion