CTechnotips: Octal to decimal conversion in c language

Octal to decimal conversion method:

To convert an octal number to decimal number multiply each digits separately of octal number from right side by  8^0,8^1,8^2,8^3 … respectively and then find out the sum of them.

Octal to decimal conversion examples:

For example we want to convert octal number 3401 to decimal number.

Step 1: 1 * 8 ^0 = 1*1 =1

Step 2: 0 * 8 ^1 = 0*8 =0

Step 3: 4 * 8 ^2 = 4*64 =256

Step 4: 3 * 8 ^3 = 3*512 =1536

Sum= 1 + 0 + 256 + 1536 = 1793

So, (3401)₈ = (1793)₁₀

C code to convert octal number to decimal number

#include<stdio.h>

#include<math.h>

int main(){

   

    long int octal,decimal =0;

    int i=0;

    printf("Enter any octal number: ");

    scanf("%ld",&octal);

    while(octal!=0){

         decimal = decimal + (octal % 10) * pow(8,i++);

         octal = octal/10;

    }

    printf("Equivalent decimal value: %ld",decimal);

   return 0;

}

Sample output:

Enter any octal number: 346

Equivalent decimal value: 230

C program to change octal to decimal

#include<stdio.h>

int main(){

   

    long int octalNumber;

    printf("Enter any octal number: ");

    scanf("%o",&octalNumber);

    printf("Equivalent decimal number is: %d",octalNumber);

    return 0;

}

Sample output:

Enter any octal number: 17

Equivalent decimal number is: 15