# C Exercises: Check if a given integer is a power of three

## C Programming Mathematics: Exercise-13 with Solution

Write a C program to check if a given integer is a power of three.

Example:

Input: 9

Output: true

Input: 81

Output: true

Input: 45

Output: false

**Pictorial Presentation:**

**Sample Solution:**

**C Code:**

```
#include <stdio.h>
#include <stdbool.h>
static bool is_PowerOf_Three(int n) {
#if 0
if (n == 1) return true;
if (n == 0 || n % 3) return false;
return is_PowerOf_Three(n / 3);
#else
return (n > 0 && (1162261467 % n) == 0);
#endif
}
int main(void)
{
int n = 9;
printf("\nIf %d is power of three? %d", n, is_PowerOf_Three(n));
n = 81;
printf("\n\nIf %d is power of three? %d", n, is_PowerOf_Three(n));
n = 45;
printf("\n\nIf %d is power of three? %d", n, is_PowerOf_Three(n));
return 0;
}
```

Sample Output:

If 9 is power of three? 1 If 81 is power of three? 1 If 45 is power of three? 0

**Flowchart: **

**C Programming Code Editor:**

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**Previous:** Write a C programming to add repeatedly all digits of a given non-negative number until the result has only one digit.

**Next:** Write a C programming to calculate the number of 1's in their binary representation and return them as an array.

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