Java Integer Division Resulting in Zero

General Discussions
, ,
1

Why does the result of 1/3 in Java division equal 0?

I wrote the following code:

public static void main(String[] args) {
    double g = 1 / 3;
    System.out.printf("%.2f", g);
}

The result is 0, but I expected a non-zero value. Why is this happening, and how can I fix this issue in Java division to get the correct result?

2

Classic integer division in Java! The issue here is that both 1 and 3 are integers, so Java performs integer division, which discards the decimal part and gives you 0. Since 0 is then assigned to g, it remains 0.00 when printed.

The fix? Use floating-point division by making at least one operand a double:

public static void main(String[] args) {
    double g = 1.0 / 3;  // Ensure at least one operand is a double
    System.out.printf("%.2f", g);  // Output: 0.33
}

Now, since 1.0 is a double, Java treats the entire expression as a floating-point operation and gives the expected result!

3

Yep, integer division strikes again! And while Miro’s solution is spot on, if you want to be extra explicit and ensure precision every time, you can cast the operands to double:

public static void main(String[] args) {
    double g = (double) 1 / (double) 3;  // Explicitly cast both operands
    System.out.printf("%.2f", g);  // Output: 0.33
}

This guarantees that java division always happens in floating-point mode. While casting both operands isn’t strictly necessary (since just one would work), it makes the intent clearer in complex expressions.

4

Exactly, floating-point division is the way to go! But if you need even more control over precision, you might want to round the result to avoid floating-point inaccuracies in certain cases. Java’s Math.round() can help:

public static void main(String[] args) {
    double g = Math.round((1.0 / 3) * 100.0) / 100.0;  // Rounds to two decimal places
    System.out.printf("%.2f", g);  // Output: 0.33
}

This ensures your result is rounded properly to two decimal places. Not always needed, but useful if you’re dealing with precise financial calculations or need to avoid floating-point quirks in java division.