Given a number N, we have to write a java program to check whether N is positive or negative numbers. If a number is greater than or equal to 0 then it is a positive number otherwise a negative number. There are multiple approaches of testing positive and negative numbers but here we will use if-else statement for decision making.
For Example :4 >= 0, => 4 is a positive number.
-2 < 0, => -2 is a negative number.
Java program to check for positive and negative number
In this program, we first take an integer as input from user and store it in a variable "num". Then using a if-else statement, we check whether "num" id >= 0 or not. If yes then print appropriate message on screen.
package com.tcc.java.programs;
import java.util.Scanner;
public class PositiveNegativeNumber {
    public static void main(String[] args) {
        int num;
        Scanner scanner;
        // Take an integer from user
        scanner = new Scanner(System.in);
        System.out.println("Enter an Integer");
        num = scanner.nextInt();
        /*
         * Using if-else statement check whether
         * num is >= 0 or not.
         */
        if (num >= 0) {
            // num is positive
            System.out.println(num + " is Positive Number");
        } else {
            // num is negative
            System.out.println(num + " is Negative Number");
        }
    }
}
Output
Enter an Integer -4 -4 is Negative Number
Enter an Integer 8 8 is Positive Number
Java program to find a number is positive or negative using a method
This java program is similar to above program except here we wrote a method "isPositive" which takes an integer as input and return true or false based of given integer is positive or negative respectively.
package com.tcc.java.programs;
import java.util.Scanner;
public class PositiveNegativeNumberFunction {
    public static void main(String[] args) {
        int num;
        Scanner scanner;
        // Take an integer from user
        scanner = new Scanner(System.in);
        System.out.println("Enter an Integer");
        num = scanner.nextInt();
        if (isPositive(num)) {
            // num is positive
            System.out.println(num + " is Positive Number");
        } else {
            // num is negative
            System.out.println(num + " is Negative Number");
        }
    }
    public static boolean isPositive(int num) {
        if (num >= 0)
            return true;
        else
            return false;
    }
}
Output
Enter an Integer -1 -1 is Negative Number
Enter an Integer 3 3 is Positive Number
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