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Convert Positive Integer to Negative in Java

Author: SAI K

In Java programming, manipulating numeric values is a fundamental aspect, and sometimes, you might find yourself needing to convert a positive integer to its negative counterpart. This conversion is a straightforward process, but understanding how to do it correctly is essential for various applications, such as mathematical computations, data transformations, or algorithm implementations. In this blog post, we'll explore how to convert a positive integer to a negative integer in Java.

1. Simple Negation Using the Unary Minus Operator

The most direct way to convert a positive integer to a negative is by using the unary minus (-) operator. This operator changes the sign of the number.

Example:

public class PositiveToNegative {
    public static void main(String[] args) {
        int positiveNumber = 50;
        int negativeNumber = -positiveNumber;

        System.out.println("Positive Number: " + positiveNumber);
        System.out.println("Converted Negative Number: " + negativeNumber);
    }
}

Output:

Positive Number: 50
Converted Negative Number: -50

In this example, the unary minus operator is used to convert the positive number 50 to -50.

2. Using Math.negateExact()

Java's Math class provides the negateExact() method, which returns the negation of the argument. This method is particularly useful as it also checks for overflow.

Example:

public class PositiveToNegative {
    public static void main(String[] args) {
        int positiveNumber = 50;
        int negativeNumber = Math.negateExact(positiveNumber);

        System.out.println("Positive Number: " + positiveNumber);
        System.out.println("Converted Negative Number: " + negativeNumber);
    }
}

Output:

Positive Number: 50
Converted Negative Number: -50

Using Math.negateExact() not only converts the number but also throws an ArithmeticException if the result overflows an int.

Handling Edge Cases

While converting positive integers to negative is straightforward in Java, it's important to be aware of edge cases, especially concerning the integer overflow.

Example of Integer Overflow:

public class PositiveToNegative {
    public static void main(String[] args) {
        int positiveNumber = Integer.MAX_VALUE;
        int negativeNumber = -positiveNumber;

        System.out.println("Positive Number: " + positiveNumber);
        System.out.println("Converted Negative Number: " + negativeNumber);
    }
}

Output:

Positive Number: 2147483647
Converted Negative Number: -2147483647

In this case, negating Integer.MAX_VALUE doesn't result in overflow, but if you were to negate Integer.MIN_VALUE, it would.

Conclusion

Converting a positive integer to a negative in Java is a simple task that can be achieved using the unary minus operator or the Math.negateExact() method. However, it's crucial to consider integer overflow and handle it appropriately in your code to ensure accuracy and prevent potential errors.

Understanding these basic yet essential concepts in Java is key to effective programming and problem-solving. Stay tuned for more informative posts on Java programming! Happy coding!


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