Check if a Number is Positive or Negative in Java

In the following section, we’ll build a program to Check if a Number is Positive or Negative in Java. By contrasting the entered number with Zero, the integer’s positive or negative nature is illustrated (0). If the user enters a number more than zero, it is positive; otherwise, if it is less than zero, it is negative; and finally, if it is zero, it is zero.

• N > 0 then, number is Positive.
• N < 0 then, number is Negative.
• N = 0 then, number is Zero.

To solve the above problem we write a Java code using three different methods.

• Method 1: Using Brute Force
• Method 2: Using Nested if-else Statements
• Method 3: Using Ternary Operators

The Above methods are discussed in depth in the sections below.

Method 1: Using Brute Force

Java Code

//Brute force
class Main
{
  public static void main (String[]args)
  {

    int num = 5;

    //Conditions to check if the number is negative or positive
    if (num > 0)
        System.out.println ("The number is positive");
    else if (num < 0)
        System.out.println ("The number is negative");
    else
        System.out.println ("Zero");
  }
}

Output

The number is positive

Algorithm

This method uses Brute Force to check whether a given integer is Positive or Negative. The Algorithm for the above code is as follows

• Step 1. Start
• Step 2. Insert the number.
• Step 3. If the number is greater than Zero then print “The number is Positive”
• Step 4: If the number is smaller than zero, then print, “The number is Negative”
• Step 5. Else print, “The number is Zero”
• Step 6. Stop

Method 2: Using Nested if-else Statements

Java Code

//Using Nested If-else statement
class Main
{
  public static void main (String[]args)
  {

    int num = 5;
    
     //Condition to check if the number is negative or positive
    if (num >= 0)
    {
        if (num == 0)
            System.out.println ("Zero");
        else
            System.out.println ("The number is positive");
    }
    else
        System.out.println ("The number is negative");

  }
}

Output

The number is positive

Algorithm

This method uses a nested if-else Statements to check whether a given number is Positive or Negative.

• Step 1 – Start
• Step 2 – Insert the number.
• Step 3 – If the number is greater or equal move to the inner nested loop
  • Step 3.1 – If the number is zero, print Zero
  • Step 3.2 – Else print The Number is Positive
• Step 4 – Else the number has to be negative, Print The number is Negative
• Step 5 – Stop

Method 3: Using Ternary Operator

Java code

//Using Ternary Operator
class Main
{
  public static void main (String[]args)
  {

    int num = 0;

    //Condition to check if the number is negative or positive

    if (num == 0)
      {
	    System.out.println ("Zero");
      }
      
    else{
        String result = num > 0 ? "The number is positive" : "The number is negative";
        System.out.println (result);
    }
  }
}

Output

Zero

Algorithm

This method uses a ternary operator to check whether a number is Positive or Negative. The Algorithm for the above code is as follows,

• Step 1 – Start
• Step 2 – Insert the number.
• Step 3 – If number is equal to zero, Print Number is Zero
• Step 4 – Else do following – (num > 0) ? cout << “Positive”: cout << “Negative”;
• Step 5 – Stop

Also read: ASCII Table