codescracker
c

C Program to Convert Octal to Decimal



« Previous Program Next Program »

In this tutorial, we will learn about how to create a program in C that can convert any given octal number into its equivalent decimal number. At last we will also take a look at function-driven program that does the same job but using user-defined function named OctToDec().

But before going through the program. If you are not aware of

then refer to Octal to Decimal conversion step by step process. Now let's move on to the program.

Octal to Decimal in C

To convert octal number to decimal number in C programming, you have to ask from user to enter the octal number first. Then convert it into decimal number, and then display the equivalent value in decimal form as output.

// Octal to Decimal in C
// ----codescracker.com----

#include<stdio.h>
#include<conio.h>
#include<math.h>
int main()
{
    int octnum, decnum=0, i=0, rem;
    printf("Enter any Octal Number: ");
    scanf("%d", &octnum);
    while(octnum!=0)
    {
        rem = octnum%10;
        decnum = decnum + (rem*pow(8,i));
        i++;
        octnum = octnum/10;
    }
    printf("\nEquivalent Decimal Value = %d", decnum);
    getch();
    return 0;
}

As the above program was written under Code::Blocks IDE, therefore after successful build and run, you will get the following output. This is the first snapshot of the sample run:

c program convert octal to decimal

Now supply any octal number say 345 as input and then press ENTER key to see the output that shows you its equivalent decimal value as shown in the second snapshot given below:

c octal to decimal

Program Explained

without pow() Function

You can also create the program without using any pow() function of math.h library. Here is the program without using any pre-defined function:

// Octal to Decimal in C without pow() Function
// ----codescracker.com----

#include<stdio.h>
#include<conio.h>
int main()
{
    int octnum, decnum=0, rem, mul=1;
    printf("Enter any Octal Number: ");
    scanf("%d", &octnum);
    while(octnum!=0)
    {
        rem = octnum%10;
        decnum = decnum + (rem*mul);
        mul = mul*8;
        octnum = octnum/10;
    }
    printf("\nEquivalent Decimal Value = %d", decnum);
    getch();
    return 0;
}

Here is the final snapshot of the above program's sample run:

octal to decimal in c

using User-defined Function

Let's create function-driven program in which the function OctToDec() created in such way, it takes one argument as octal number, and converts it into its equivalent decimal value and then return it to the main() function as shown in the program given below:

// Octal to Decimal in C using Function
// ----codescracker.com----

#include<stdio.h>
#include<conio.h>
int OctToDec(int oct);
int main()
{
    int octnum, decnum=0, rem, mul=1;
    printf("Enter any Octal Number: ");
    scanf("%d", &octnum);
    decnum = OctToDec(octnum);
    printf("\nEquivalent Decimal Value = %d", decnum);
    getch();
    return 0;
}
int OctToDec(int oct)
{
    int rem, dec=0, mul=1;
    while(oct!=0)
    {
        rem = oct%10;
        dec = dec + (rem*mul);
        mul = mul*8;
        oct = oct/10;
    }
    return dec;
}

The final snapshot of the above program's sample run is given below:

c octal to decimal using function

Same Program in Other Languages

C Online Test


« Previous Program Next Program »



© Copyright 2021. All Rights Reserved.

CodesCracker