Problem: Write a C program to convert a decimal number into an Octal number.
Example:
1 2 3 4 5 | Input: 7 Output: 7 Input: 8 Output: 10 |
Decimal to Octal using While Loop
The following picture depicts the standard way of converting a number from decimal number system to octal number system.
To implement the same in C, we divide the decimal number by 8 until the number reduces to 0 using while loop and in the meantime, we also concatenate each remainder according to bottom-up approach (i.e to the left of the concatenated remainder).
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 | #include <stdio.h> #include <stdlib.h> int main() { int n, octal=0, rem, i=1; //Input the decimal number printf("Enter a Decimal number \n"); scanf("%d",&n); //While loop will run until n becomes by dividing it by 8 while(n != 0) { rem = n%8; octal = (rem*i) + octal; //adding the remainder on left of octal n = n/8; i= i*10; //update i, so that on next iteration, // rem will be added to left of octal } printf("Octal: %d", octal); return 0; } |
Output
Decimal to Octal using Recursion
The concept used in this method is the same as the above. The only difference is that, it is implemented using recursion.
Since, recursion implements stack, it is the best way to print remainder from bottom to top.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 | #include <stdio.h> #include <stdlib.h> void decToOct(int n){ if(n > 0){ //recall by passing quotient decToOct(n/8); //print remainder printf("%d",n%8); } } int main() { int n; //Input the decimal number printf("Enter a Decimal number \n"); scanf("%d",&n); printf("Octal: "); decToOct(n); return 0; } |
Output
In this tutorial, we learned to convert the decimal number to its octal representation using c programming language.