# Count total bits in a number

Given a positive number n, count total bit in it.**Examples:**

Input : 13 Output : 4 Binary representation of 13 is 1101 Input : 183 Output : 8 Input : 4096 Output : 13

**Method 1 (Using Log)**

The log2(n) logarithm in base 2 of n, which is the exponent to which 2 is raised to get n only integer and we add 1 find total bit in a number in log(n) time.

## C++

`// C++ program to find total bit in given number` `#include <iostream> ` `#include <cmath>` `unsigned countBits(unsigned ` `int` `number)` `{ ` ` ` ` ` `// log function in base 2` ` ` `// take only integer part` ` ` `return` `(` `int` `)log2(number)+1;` `}` `// Driven program ` `int` `main()` `{` ` ` `unsigned ` `int` `num = 65;` ` ` `std::cout<<countBits(num)<<` `'\n'` `;` ` ` `return` `0;` `}` `// This code is contributed by thedev05.` |

## C

`// C program to find total bit in given number` `#include <stdio.h> ` `#include <math.h>` `unsigned countBits(unsigned ` `int` `number)` `{ ` ` ` `// log function in base 2` ` ` `// take only integer part` ` ` `return` `(` `int` `)log2(number)+1;` `}` `// Driven program ` `int` `main()` `{` ` ` `unsigned ` `int` `num = 65;` ` ` `printf` `(` `"%d\n"` `, countBits(num));` ` ` `return` `0;` `}` |

## Java

`// Java program to` `// find total bit` `// in given number` `import` `java.io.*;` `class` `GFG` `{` ` ` `static` `int` `countBits(` `int` `number)` ` ` `{` ` ` ` ` `// log function in base 2` ` ` `// take only integer part` ` ` `return` `(` `int` `)(Math.log(number) /` ` ` `Math.log(` `2` `) + ` `1` `);` ` ` `}` ` ` ` ` `// Driver code` ` ` `public` `static` `void` `main (String[] args)` ` ` `{` ` ` `int` `num = ` `65` `;` ` ` ` ` `System.out.println(countBits(num));` ` ` ` ` `}` `}` `// This code is contributed by vij` |

## Python3

`# Python3 program to find` `# total bit in given number` `import` `math` `def` `countBits(number):` ` ` ` ` `# log function in base 2` ` ` `# take only integer part` ` ` `return` `int` `((math.log(number) ` `/` ` ` `math.log(` `2` `)) ` `+` `1` `);` `# Driver Code` `num ` `=` `65` `;` `print` `(countBits(num));` `# This code is contributed by mits` |

## C#

`// C# program to find total bit` `// in given number` `using` `System;` `class` `GFG {` ` ` ` ` `static` `uint` `countBits(` `uint` `number)` ` ` `{ ` ` ` ` ` `// log function in base 2` ` ` `// take only integer part` ` ` `return` `(` `uint` `)Math.Log(number , 2.0) + 1;` ` ` `}` ` ` ` ` `// Driver code` ` ` `public` `static` `void` `Main()` ` ` `{` ` ` `uint` `num = 65;` ` ` ` ` `Console.WriteLine(countBits(num));` ` ` ` ` `}` `}` `// This code is contributed by Sam007.` |

## PHP

`<?php` `// PHP program to find total` `// bit in given number` `function` `countBits(` `$number` `)` `{` ` ` ` ` `// log function in base 2` ` ` `// take only integer part` ` ` `return` `(int)(log(` `$number` `) /` ` ` `log(2)) + 1;` `}` `// Driver Code` `$num` `= 65;` `echo` `(countBits(` `$num` `));` `// This code is contributed by Ajit.` `?>` |

## Javascript

`<script>` `// JavaScript program to find total bit in given number` ` ` `function` `countBits(number) { ` ` ` `// log function in base 2 ` ` ` `// take only integer part` ` ` `return` `Math.floor(Math.log2(number)+1);` ` ` `}` ` ` ` ` `// Driven program ` ` ` `let num = 65;` ` ` `document.write(countBits(num));` ` ` `// This code is contributed by Surbhi Tyagi` `</script>` |

**Output**

7

**Time Complexity : **O(logn)

**Auxiliary Space :** O(1)

**Method 2 (Using Bit Traversal)**

## C

`/* Function to get no of bits in binary` ` ` `representation of positive integer */` `#include <stdio.h> ` ` ` `unsigned ` `int` `countBits(unsigned ` `int` `n)` `{` ` ` `unsigned ` `int` `count = 0;` ` ` `while` `(n)` ` ` `{` ` ` `count++;` ` ` `n >>= 1;` ` ` `}` ` ` `return` `count;` `}` ` ` `/* Driver program*/` `int` `main()` `{` ` ` `int` `i = 65;` ` ` `printf` `(` `"%d"` `, countBits(i));` ` ` `return` `0;` `}` |

## Java

`/* Function to get no of bits in binary` `representation of positive integer */` `class` `GFG {` ` ` `static` `int` `countBits(` `int` `n)` ` ` `{` ` ` `int` `count = ` `0` `;` ` ` `while` `(n != ` `0` `)` ` ` `{` ` ` `count++;` ` ` `n >>= ` `1` `;` ` ` `}` ` ` ` ` `return` `count;` ` ` `}` ` ` ` ` `/* Driver program*/` ` ` `public` `static` `void` `main(String[] arg)` ` ` `{` ` ` `int` `i = ` `65` `;` ` ` `System.out.print(countBits(i));` ` ` `}` `}` `// This code is contributed by Smitha.` |

## Python3

`# Function to get no of bits` `# in binary representation` `# of positive integer` `def` `countBits(n):` ` ` `count ` `=` `0` ` ` `while` `(n):` ` ` `count ` `+` `=` `1` ` ` `n >>` `=` `1` ` ` ` ` `return` `count` `# Driver program` `i ` `=` `65` `print` `(countBits(i))` `# This code is contributed` `# by Smitha` |

## C#

`/* Function to get no of bits` `in binary representation of` `positive integer */` `using` `System;` `class` `GFG` `{` ` ` `static` `int` `countBits(` `int` `n)` ` ` `{` ` ` `int` `count = 0;` ` ` `while` `(n != 0)` ` ` `{` ` ` `count++;` ` ` `n >>= 1;` ` ` `}` ` ` ` ` `return` `count;` ` ` `}` ` ` ` ` `// Driver Code` ` ` `static` `public` `void` `Main ()` ` ` `{` ` ` `int` `i = 65;` ` ` `Console.Write(countBits(i));` ` ` `}` `}` `// This code is contributed` `// by akt_mit.` |

## PHP

`<?php` `// PHP Code to get no of bits in binary` `// representation of positive integer` `// Function to get no of bits in binary` `// representation of positive integer` `function` `countBits(` `$n` `)` `{` ` ` `$count` `= 0;` ` ` `while` `(` `$n` `)` ` ` `{` ` ` `$count` `++;` ` ` `$n` `>>= 1;` ` ` `}` ` ` `return` `$count` `;` `}` `// Driver Code` `$i` `= 65;` `echo` `(countBits(` `$i` `));` `// This code is contributed by Ajit.` `?>` |

## Javascript

`<script>` `/* Function to get no of bits` `in binary representation of` `positive integer */` `function` `countBits(n)` `{` ` ` `var` `count = 0;` ` ` `while` `(n != 0)` ` ` `{` ` ` `count++;` ` ` `n >>= 1;` ` ` `}` ` ` ` ` `return` `count;` `}` `// Driver Code` `var` `i = 65;` `document.write(countBits(i));` `</script>` |

**Output**

7

**Time Complexity : **O(logn)

**Auxiliary Space :** O(1)

**Method 3 ( Using conversion from binary to string)**

## Python3

`# function to count the number of bits in a number n` `def` `count_bits(n):` ` ` `# bin(n) returns a binary string representation of n preceded by '0b' in python` ` ` `binary ` `=` `bin` `(n)` ` ` ` ` `# we did -2 from length of binary string to ignore '0b'` ` ` `return` `len` `(binary)` `-` `2` `a ` `=` `65` `b ` `=` `183` `print` `(f` `"Total bits in {a}: {count_bits(a)}"` `)` `print` `(f` `"Total bits in {b}: {count_bits(b)}"` `)` `# This code is contributed by udit` |

**Output**

Total bits : 7 Total bits : 8

**Time Complexity : **O(logn)

**Auxiliary Space :** O(1)

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