Convert Octal to Binary

The C program carry out number system conversion from a octal value (base-8) to binary numbers (base-2) is called octal to binary conversion. A octal number is represented by binary 3 bits.

Octal number system

The octal number system has the following unique digits.
{0, 1, 2, 3, 4, 5, 6, 7}

As the octal number system has the 8 unique digits, it is called base 8 or radix 8 number system.

Each octal digit can be represented by binary 3 bits.

Binary number system

The Binary number system has the following unique digits.
{0, 1}

As the binary number system has the 2 unique digits, it is called base 2 or radix 2 number system.

The computer can only understand this number system and is operated by this binary number system, therefore it accepts data,instruction and everything in binary numbers format.

Octal to Binary conversion example

    
       The given octal number is 653 and 
           converts it into binary numbers

         octal = 653 , binary = ?
            
         split each digit of octal given number and
            carried out decimal to 3 bits binary conversion on each octal digit  
                

       octal =     6  |  5  |  3
       binary =   110   101   011

      if octal = 653 and equivalent binary = 110101011
 
  

Octal to Binary - C program code

The C program converts octal number into binary number. The program reads octal number from user and executes conversion process and returns binary numbers as result.

 

#include<stdio.h>
#include<string.h>
#include<math.h>
#include<stdlib.h>


char* dec2bin(int decval) 
{
    char *bits=(char*) malloc(sizeof(char)*4);
    int n=0;  int bpo=3;
    for(int n=0;n<bpo;n++)   
     {     
        int reminder= decval %2;
        decval  = decval /2;       
        bits[bpo-n-1] = (reminder==1) ? '1' : '0';        
     }  
  bits[bpo] = '\0';  
  return bits;
}

int oct2dec(char ox) {

   int decval=0;
   
   switch (ox) 
    {   
  case '1' :
     decval=1;
  break;
  case '2':
     decval=2;
  break;
 case '3':
     decval=3;
  break;
 case '4':
     decval=4;
  break;
 case '5':
     decval=5;
  break;
 case '6':
     decval=6;
  break;
 case '7':
     decval=7;
  break;     
 default:
        decval =0;  
 }
 
 return decval;
   
}

int main() {

   int mxoct =5; 
   char oct[mxoct+1];    
   char *bits;    
   
   printf("\n Octal to Binary Conversion");   
   printf("\n Enter octal value :") ;
   scanf("%s",&oct);
   
   for(int n=0;n<strlen(oct);n++) {
   
      int decval = oct2dec(oct[n]);   
      char *b3s = dec2bin(decval);
   strcat(bits,b3s);
   //printf("\n %c \t %d \t %s",oct[n],decval,dec2bin(decval));
   
   }
   
   printf("\nOctal value : %s", oct); 
   printf("\nBinary bits : %s ",bits);
   return 0;
}

 

Octal to Binary conversion - C program Output

 Octal to Binary Conversion
 Enter octal value :546

 Octal value : 546
 Binary bits :101100110

Related post

• Decimal to binary using arithmetic operator
• Binary to decimal using arithmetic operator
• Decimal to 8 bit binary using arithmetic operator
• Decimal to binary using bitwise right-shift operator
• Binary to Decimal using bitwise right-shift operator
• Decimal to binary using bitwise left-shift operator
• Binary to Decimal using bitwise left-shift operator
• Binary to Octal number system conversion
• Hexadecimal to Binary number system conversion
• Binary to Hexadecimal number system conversion

Download c program source code

• Octal to binary