C program to convert a Binary number into its equivalent Decimal, Octal and Hexadecimal numbers.

Posted on by Sandeepa Nadahalli

C Program to convert binary number into its equivalent Decimal, Octal, and Hexadecimal representations. In this program we convert a binary number to decimal. Then convert that decimal number to octal and Hexadecimal equivalent.

The program implements various functions to do the job.

  • binary_to_decimal : Convert given binary number to it’s decimal equivalent
  • decimal_to_octal : Convert from decimal to octal
  • decimal_to_hex : Convert from decimal to hexadecimal

The main function takes care of getting input from user, calling the above functions and displaying the results.

Read more here: What are binary, octal, and hexadecimal notation?

The Program

#include <stdio.h>
/*
* Function to convert a given decimal number to its
* hexadecimal equivalent.
*/
int decimal_to_hex(long number, char *hexstr, int pos) {
long i;
int new_position, n;
char hexchar;
new_position = pos;
if(number > 0) {
i = number % 16;
n = number / 16;
new_position = decimal_to_hex(n, hexstr, pos);
if(i >= 10) {
switch(i) {
case 10: hexchar = 'A'; break;
case 11: hexchar = 'B'; break;
case 12: hexchar = 'C'; break;
case 13: hexchar = 'D'; break;
case 14: hexchar = 'E'; break;
case 15: hexchar = 'F'; break;
}
} else {
hexchar = '0' + i;
}
hexstr[new_position++] = hexchar;
hexstr[new_position] = '\0';
}
return new_position;
}
/*
* Function to convert a given binary number to
* its decimal equivalent.
*/
int binary_to_decimal(int num) {
int rem, base = 1, decimal_number = 0;
while( num > 0) {
rem = num % 10;
if((rem == 0) || (rem == 1)) {
decimal_number = decimal_number + rem * base;
num = num / 10 ;
base = base * 2;
} else {
return -1; // Invalid binary number
}
}
return decimal_number;
}
/*
* Function to convert a given decimal number in to
* its octal equivalent.
*/
int decimal_to_octal(int number) {
int octal_number = 0, rem, base = 1;
while(number > 0) {
rem = number % 8;
octal_number = octal_number + rem * base;
base = base * 10;
number = number / 8;
}
return octal_number;
}
void main() {
int binary_numer, decimal_number, octal_number;
char hexstr[25] = "0";
printf("Enter a binary number: ");
scanf("%d", &binary_numer);
printf("Given Binary number is: %d\n", binary_numer);
decimal_number = binary_to_decimal(binary_numer);
if(decimal_number == -1) {
printf("\nInvalid binary number. Try again.");
return;
}
printf("Its Decimal equivalent is: %d", decimal_number);
octal_number = decimal_to_octal(decimal_number);
printf("\nIts octal equivalent is: %d", octal_number);
decimal_to_hex(decimal_number, hexstr, 0);
printf("\nIts Hexa Decimal equivalent is: %s", hexstr);
}
view raw binary_to_octal_decimal_hexadecimal.c hosted with ❤ by GitHub

Sample Output

Binary to decimal, binary to octal, binary to hexadecimal

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Edit1 : 11th August 2017

  • Added screenshot of sample runs
  • Moved the code to it’s own Gist
  • Modified the program to make it more modular

(c) www.c-program-example.com

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