C Exercises: Convert an octal number into binary

C For Loop: Exercise-54 with Solution

Write a program in C to convert an octal number into binary.

Visual Presentation:

Sample Solution:

C Code:

#include <stdio.h>  // Include the standard input/output header file. 
#include <math.h>   // Include the math header file.
int main() {
    // Declare variables  
    long int n1, n5, p = 1;
    long int dec = 0, i = 1, j, d;
    long int binno = 0;

    // Print output headers
    printf("\n\nConvert Octal to Binary:\n");
    printf("-------------------------\n");

    // Get octal input
    printf("Input an octal number (using digits 0 - 7): ");
    scanf("%ld", &n1);
    
    // Store input number
    n5 = n1;

    // Convert octal to decimal
    // Loop through each octal digit
    for (j = n1; j > 0; j = j / 10) {
        // Get current digit
        d = j % 10;
        
        // Update power of 8
        if (i == 1) {
            p = p * 1;
        } else {
            p = p * 8;
        }
        
        // Add digit * power of 8 to result
        dec = dec + (d * p);
        
        // Increment power 
        i++;
    }

    // Convert decimal to binary
    i = 1; // Reset power

    // Repeatedly divide decimal by 2
    for (j = dec; j > 0; j = j / 2) {
        // Get remainder and add to result
        binno = binno + (dec % 2) * i;
        
        // Update power of 2
        i = i * 10;
        
        // Divide decimal
        dec = dec / 2;
    }

    // Print octal and binary result
    printf("\nThe Octal Number: %ld\nThe equivalent Binary Number: %ld\n\n", n5, binno);

    return 0; // Indicate successful completion of the program
}

Sample Output:

Convert Octal to Binary:                                                                                      
 -------------------------                                                                                    
Input an octal number (using digit 0 - 7) :57                                                                 
                                                                                                              
The Octal Number : 57                                                                                         
The equivalent Binary  Number : 101111 

Flowchart:

C Programming Code Editor:

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