# C Exercises: Test whether a non-negative number is a multiple of 13 or it is one more than a multiple of 13

## C-programming basic algorithm: Exercise-19 with Solution

Write a C program that checks if a given non-negative integer is a multiple of 13 or one more than a multiple of 13. For example, if the given integer is 26 or 27, the program will return true, but if it is 25 or 28, the program will return false.

**C Code:**

```
#include <stdio.h> // Include standard input/output library
#include <stdlib.h> // Include standard library for additional functions
// Function declaration for 'test' with an integer parameter 'n'
int test(int n);
int main(void){
// Print the result of calling 'test' with different integer values and format the output
printf("%d",test(13));
printf("\n%d",test(14));
printf("\n%d",test(27));
printf("\n%d",test(41));
}
// Function definition for 'test'
int test(int n)
{
// Check if 'n' is divisible by 13 or if the remainder of 'n' divided by 13 is 1
if (n % 13 == 0 || n % 13 == 1) {
return 1; // If any of the conditions are met, return 1 (true)
} else {
return 0; // If none of the conditions are met, return 0 (false)
}
}
```

Sample Output:

1 1 1 0

**Explanation:**

int test(int n) { return n % 13 == 0 || n % 13 == 1; }

The function takes an integer n as input and returns a boolean value. It checks if n is a multiple of 13 or if n is one more than a multiple of 13. If either condition is true, it returns true; otherwise, it returns false.

**Time complexity and space complexity:**

The time complexity of the function is O(1) because it performs a simple arithmetic operation (modulus) on a single input integer.

The space complexity of the function is O(1) because it only uses a few integer variables to store the input and intermediate calculations.

**Flowchart:**

**C Programming Code Editor:**

**Previous:** Write a C program that accept two integers and return true if either one is 5 or their sum or difference is 5.

**Next:** Write a C program to check whether a given non-negative number is a multiple of 3 or 7, but not both.

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