CTechnotips: Binary to octal conversion in c language

Binary to octal conversion method:

Step1: Arrange the binary number in the group 3 from right side.

Step 2:  Replace the each group with following values:

Binary number	Octal values
000	0
001	1
010	2
011	3
100	4
101	5
110	6
111	7

Binary to octal chart  

Binary to octal conversion examples:

For example we want to convert binary number 1011010101001101 to octal.

Step 1: 001 011 010 101 001 101

Step 2:  1   3   2   5   1   5

So (1011010101001101)₂ = (132515)₈

C program c program to convert binary to octal

#include<stdio.h>

int main(){

   

    long int binaryNumber,octalNumber=0,j=1,remainder;

    printf("Enter any number any binary number: ");

    scanf("%ld",&binaryNumber);

    while(binaryNumber!=0){

         remainder=binaryNumber%10;

        octalNumber=octalNumber+remainder*j;

        j=j*2;

        binaryNumber=binaryNumber/10;

    }

    printf("Equivalent octal value: %lo",octalNumber);

    return 0;

}

Sample output:

Enter any number any binary number: 1101

Equivalent hexadecimal value: 15

C code for how to convert large binary to octal

#include<stdio.h>

#define MAX 1000

int main(){

   

    char binaryNumber[MAX],octalNumber[MAX];

    long int i=0,j=0;

    printf("Enter any number any binary number: ");

    scanf("%s",binaryNumber);

    while(binaryNumber[i]){

      binaryNumber[i] = binaryNumber[i] -48;

      ++i;

    }

    --i;

    while(i-2>=0){

    octalNumber[j++] = binaryNumber[i-2] *4 +  binaryNumber[i-1] *2 + binaryNumber[i] ;

    i=i-3;

    }

    if(i ==1)

      octalNumber[j] = binaryNumber[i-1] *2 + binaryNumber[i] ;

    else if(i==0)

      octalNumber[j] =  binaryNumber[i] ;

    else

      --j;

    printf("Equivalent octal value: ");

    while(j>=0){

      printf("%d",octalNumber[j--]);

    }

    return 0;

}

Sample output:

Enter any number any binary number: 1111111111111111111

1111111111111111111111111111111111111111111111111111111

1111111111111111111111111111111111111111111111111111111
1111111111111111111111111111111111111111111111111111111
1111111111111111111111111111111111111111111111111111111
11111111

Equivalent octal value: 3777777777777777777777777777777

7777777777777777777777777777777777777777777777777777