# C program to convert Decimal to Octal number

In this article, we are going to learn the C program to convert Decimal to Octal numbers. Here we are going to learn about two numbers one is octal and another is Decimal. Octal numbers are base 8 numbers and are represented in numbers from 0 to 7. Decimal numbers are base 10 numbers and are represented in numbers from 0 to 9.

### Program to convert decimal to octal number

In this c program, we are asking users to input decimal number and by using some logic in the below program convert them to octal numbers.

```#include <stdio.h>

int main()
{
long long decimalNum, tmpDecimalNo;
long long octalNum;
int i, rem, place = 1;

octalNum = 0;

printf("Please enter the decimal number: ");
scanf("%lld", &decimalNum);

tmpDecimalNo = decimalNum;

while(tmpDecimalNo > 0)
{
rem = tmpDecimalNo % 8;

octalNum = (rem * place) + octalNum;

tmpDecimalNo = tmpDecimalNo/8;

place *= 10;
}

printf("\nDecimal number = %lld\n", decimalNum);
printf("Octal number = %lld", octalNum);

return 0;
}
```

Output

```Please enter the decimal number: 11

Decimal number = 11
Octal number = 13
```