Octal number system: It is base 8 number system which uses the digits from 0 to 7.
Decimal number system:
It is base 10 number system which uses the digits from 0 to 9
Decimal to octal conversion method:
Step 1: Divide the original decimal number by 8
Step 2: Divide the quotient by 8
Step3: Repeat the step 2 until we get quotient equal to zero.
Result octal number would be remainders of each step in the reverse order.
Decimal to octal conversion with example:
For example we want to convert decimal number 525 in the octal.
Step 1: 525 / 8 Remainder : 5 , Quotient : 65
Step 2: 65 / 8 Remainder : 1 , Quotient : 8
Step 3: 8 / 8 Remainder : 0 , Quotient : 1
Step 4: 1 / 8 Remainder : 1 , Quotient : 0
So equivalent octal number is: 1015
That is (525)10 = (1015)8
C Program 1
#include<stdio.h> int main() { long int decimalNumber,remainder,quotient; int octalNumber[100],i=1,j; printf("Enter any decimal number: "); scanf("%ld",&decimalNumber); quotient = decimalNumber; while(quotient!=0) { octalNumber[i++]= quotient % 8; quotient = quotient / 8; } printf("Equivalent octal value of decimal number %d: ",decimalNumber); for (j = i -1 ;j> 0;j--) printf("%d",octalNumber[j]); return 0; }
Output 1
Enter any decimal number: 50 Equivalent octal value of decimal number 50: 62
C Program 2
#include<stdio.h> int main() { long int decimalNumber; printf("Enter any decimal number : "); scanf("%d",&decimalNumber); printf("Equivalent octal number is: %o",decimalNumber); return 0; }
Output 2
Enter any decimal number: 25 Equivalent octal number is: 31