C Program to Convert Decimal to Octal Number

In this article, we will show you, How to write a C Program to Convert Decimal to Octal Number with a practical example.

As we all know,

• Decimal values are base 10 number systems, and they use numbers between 0 and 9
• The octal numbers are Numbers of base 8, and they are they use numbers between 0 and 7

To convert Decimal Number to Binary Number – First, Divide Original value with 8. Next, Divide the Quotient by 8. Repeat the same procedure until the given number is zero.

C Program to Convert Decimal to Octal Number Example 1

This is the simplest and better approach to convert decimal numbers to octal numbers

/* C Program to Convert Decimal to Octal Number */
 
#include <stdio.h>
int main() 
{
    int number;
    printf("\n Please Enter the Number You want to Convert  :  ");
    scanf("%d", &number);
    
    printf("\n Octal Number of a Given Number =  %o”, number);

    return 0;
}

OUTPUT

C Program to Convert Decimal to Octal Number Example 2

This program allows the user to enter any numeric value. Next, we used For Loop to convert the user given Decimal value to Octal value. Finally, we used the For Loop to print Array elements. I suggest you refer Print Array article

/* C Program to Convert Decimal to Octal Number */
 
#include <stdio.h>
int main() 
{
    int octalNumber[10], number, i, j;
    printf("\n Please Enter the Number You want to Convert  :  ");
    scanf("%d", &number);
    
    for(i = 0; number > 0; i++)
    {
        octalNumber[i] = number % 8;
        number = number / 8;
    }
    
    printf("\n Equivalent Octal Number of a Given Number =  ");
    for(j = i - 1; j >= 0; j--)  
    {
        printf("%d", octalNumber[j]);
    }
    return 0;
}

OUTPUT

C Program to Convert Decimal to Octal Number 3

This program is the same as above. Here, we just replaced the For Lop with While Loop. I suggest you refer While Loop to understand the Loop iterations.

/* C Program to Convert Decimal to Octal Number */
 
#include <stdio.h>
 
int main() 
{
    int octalNumber[10], number, i, j;
    printf("\n Please Enter the Number You want to Convert  :  ");
    scanf("%d", &number);
    
    while(number != 0)
    {
        octalNumber[i++] = number % 8;
        number = number / 8;
    }
    
    printf("\n Equivalent Octal Number of a Given Number =  ");
    for(j = i - 1; j > 0; j--)  
    {
        printf("%d", octalNumber[j]);
    }
    return 0;
}

OUTPUT

C Program to Convert Decimal to Octal Number Example 4

In this program, we used Functions concept to separate the logic.

/* C Program to Convert Decimal to Octal Number */
 
#include <stdio.h>

long Decimal_to_Octal(int number)
{
    long octalNumber = 0, i = 1;
    int remainder;
    while(number != 0)
    {
        remainder = number % 8;
        number = number / 8;
        octalNumber = octalNumber + (remainder * i);
        i = i * 10;
    }
    return octalNumber;
}

int main() 
{
    int number, i, j;
    printf("\n Please Enter the Number You want to Convert  :  ");
    scanf("%d", &number);
    
    long oct  = Decimal_to_Octal(number);
    printf("\n Equivalent Octal Number of %d =  %ld", number, oct);
    
    return 0;
}

OUTPUT

C Program to Convert Decimal to Octal Number Example 5

This is another approach to convert decimals numbers to octal numbers

/* C Program to Convert Decimal to Octal Number */
 
#include <stdio.h>

long Decimal_to_Octal(int number)
{
    long octalNumber = 0, i = 1;
    int remainder, count = 0;
    while(number != 0)
    {
        remainder = number % 8;
        number = number / 8;
        octalNumber = octalNumber + remainder * pow(10, count);
        count++;
    }
    return octalNumber;
}

int main() 
{
    int number, i, j;
    printf("\n Please Enter the Number You want to Convert  :  ");
    scanf("%d", &number);
    
    long oct  = Decimal_to_Octal(number);
    printf("\n Equivalent Octal Number of %d =  %ld", number, oct);
    
    return 0;
}

OUTPUT