C Program to Convert Binary to Octal Number System
June 5, 2021

This C Program converts a binary number to an equivalent octal number.
Example: Program to convert Binary to Octal
In this program, user is asked to enter the binary number and the program then converts that binary number to the octal number by calling a user defined function. To understand this program, you should be familiar with the following C programming concepts:
- C – while loop
- C – Functions
#include <stdio.h> #include <math.h> //This function converts binary number to octal number int binaryToOctal(long binarynum) { int octalnum = 0, decimalnum = 0, i = 0; /* This while loop converts binary number "binarynum" to the * decimal number "decimalnum" */ while(binarynum != 0) { decimalnum = decimalnum + (binarynum%10) * pow(2,i); i++; binarynum = binarynum / 10; } //i is re-initialized i = 1; /* This loop converts the decimal number "decimalnum" to the octal * number "octalnum" */ while (decimalnum != 0) { octalnum = octalnum + (decimalnum % 8) * i; decimalnum = decimalnum / 8; i = i * 10; } //Returning the octal number that we got from binary number return octalnum; } int main() { long binarynum; printf("Enter a binary number: "); scanf("%ld", &binarynum); // calling the function here printf("Equivalent octal value: %d", binaryToOctal(binarynum)); return 0; }
Output:
Enter a binary number: 111001 Equivalent octal value: 71