C Program to Check Whether a Number is Positive or Negative or Zero

Write a C program to check whether a given number is positive, negative, or zero.

Examples

Input: 10
Output: Positive
Explanation: Since 10 is greater than 0, it is positive.

Input: -5
Output: Negative
Explanation: Since -5 is less than 0, it is negative.

Different Ways to Check for Positive Numbers, Negative Numbers, or Zero in C

There are two ways to check whether a given number is positive, negative, or zero:

1. Using Conditional Statements Like if-else

The idea is to use simple if-else-if ladder to check for the equality manually. First use if statement for zero, then else if statement of less than zero numbers (negative) and finally if nothing matches, then it is positive numbers.

Implementation

Positive

Time Complexity: O(1)
Auxiliary Space: O(1)

2. Using Bit Operators

The most significant bit (MSB) in the binary representation of an integer is the sign bit. For positive numbers, the sign bit is 0, and for negative numbers, the sign bit is 1. By extracting the MSB from the number, we can determine the sign of the given number. For zero, we have to check it in the same way as previous method.

Implementation

Positive

Time Complexity: O(1)
Auxiliary Space: O(1)

• Bitwise Operators in C
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