C program to check if a number is positive or negative has been shown here. A number n is said to be positive if it is greater than 0 i.e. n > 0 and it is considered as negative if it is less than 0 i.e. n < 0. If n = 0, then it is neither positive nor negative.

The following sections cover the algorithm, pseudocode, time complexity and a C program to determine if a number is either positive or negative by using the above logic.

## 1. Algorithm to check if a number is positive or negative

// $n$ is an input number//

1. If $n\gt0$, then Return Positive else

2. If $n=0$, then Return Neither positive nor negative else

3. Return Negative

## 2. Pseudocode to check if a number is positive or negative

Input: A number $n$

Output: If $n$ is positive or negaive

1. Procedure positiveOrNegative($n$):

2. If $n\gt0$:

3. Return positive

4. Else:

5. If $n==0$:

6. Return Neither positive nor negative

7. Else:

8. Return negative

9. End Procedure

## 3. Time complexity to check if a number is positive or negative

Time Complexity: O(1)

## 4. C Program to check if a number is positive or negative

Code has been copied
/*******************************************************
alphabetacoder.com
C program to check if a number is positive or negative
********************************************************/

#include <stdio.h>

int main() {
// declare variable
int n;
//take input
printf("Enter the number = ");
scanf("%d", & n);

//check if n is postive or negative
if (n > 0)
printf("%d is positive", n);
else {
if (n == 0)
printf("%d is neither positive nor negative", n);
else
printf("%d is negative", n);
}
return 0;
}


Output

#### Case 1:

Enter the number = -8

-8 is negative

#### Case 2:

Enter the number = 10

10 is positive

#### Case 3:

Enter the number = 0

0 is neither positive nor negative