C Programming Code Examples C > Conversions Code Examples program takes the decimal number as input and converts it into an octal number program takes the decimal number as input and converts it into an octal number In this program, we have created a user defined function decimalToOctal() for decimal to octal conversion. The program takes the decimal number(entered by user) as input and converts it into an octal number using the function. To understand this program, you should be familiar with the following C programming concepts: #include <stdio.h> #include <math.h> /* This function converts the decimal number "decimalnum" to the equivalent octal number */ int decimalToOctal(int decimalnum) { int octalnum = 0, temp = 1; while (decimalnum != 0) { octalnum = octalnum + (decimalnum % 8) * temp; decimalnum = decimalnum / 8; temp = temp * 10; } return octalnum; } int main() { int decimalnum; printf("Enter a Decimal Number: "); scanf("%d", &decimalnum); printf("Equivalent Octal Number: %d", decimalToOctal(decimalnum)); return 0; }