Check If a Number Is Greater Than Zero in C++

Problem Description

In this problem, we are given a number and have to check whether this number is greater than zero. Using the if-else and ternary approach to check if the given number is greater than zero, equal to zero, or less than zero. In this article, we will discuss how we can find if a given number is greater than zero or not in C++.

Prerequisite

If-else operator: This operator allows the program to execute certain code blocks based on whether a condition is true or false.

Syntax of If-else operator

if (condition) {
    // Code to execute if the condition is true
} else {
    // Code to execute if the condition is false
}

Ternary Operator: This operator is also called a conditional operator. It is a compact form of an if-else statement.

Syntax of Ternary operator

condition ? expression1 : expression2;

Example 1

• Input: 4
• Output: True

Explanation

As 4 > 0, so the function will return true.

Example 2

• Input: 0
• Output: False

Explanation

0 equals 0, not greater than it. So, this function will return false.

Example 3

• Input: -3
• Output: False

Explanation

As 0 > -3, so this function will return false.

Approaches to check if a number is greater than Zero

Using If-else Operator

This is a simple and direct approach. In this approach, we check if a number is greater than zero or not using the if-else operator. If the number is greater than zero, we print "Number is greater than zero". If the number is smaller than zero, we print "Number is less than zero". If the number equals zero, we print "Number is equal to zero".

Example 1

• Input: 5
• Output: The number is greater than zero

Explanation

As 5 > 0 the output is "Number is greater than zero"

Implementation Code

#include<bits/stdc++.h>
using namespace std;
void checkNumber(int number) {
    if (number > 0) {
        cout << "The Number is greater than zero" << endl;
    } else if( number < 0) {
        cout << "The Number is less than zero" << endl;
    } else {
        cout << "The Number is equal to zero" << endl;
    }
}
int main() {
    int number = 5;
    checkNumber(number);
    return 0;
}

Output

The number is greater than zero

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

Using Ternary Operator

The logic of this approach is the same as the above approach. This is also a simple approach to check if a number is greater than zero or not using a ternary operator. If the number exceeds zero, we print "Number is greater than zero". If the number is smaller than zero, we print "Number is less than zero". If the number equals zero, we print "Number is equal to zero".

Example

• Input: -3
• Output: Number is less than zero

Explanation

As -3 < 0, the output is "Number is less than zero"

Implementation Code

#include<bits/stdc++.h>
using namespace std;
void checkNumber(int number) {
    string result = (number > 0) ? "The Number is greater than zero" :
                    (number < 0) ? "The Number is less than zero" :
                    "The Number is equal to zero";
    cout << result << endl;
}
int main() {
    int number = -3;
    checkNumber(number);
    return 0;
}

Output

The Number is less than zero

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