TheAlgorithms/Java · error · IllegalArgumentException

slant height must be greater than 0

Error message

slant height must be greater than 0

What it means

Thrown by Area.surfaceAreaPyramid when slantHeight <= 0, after sideLength has already passed its guard. The message 'slant height must be greater than 0' correctly identifies the field (note the lowercase 'slant', inconsistent with the Title-Case style used elsewhere in the class).

Source

Thrown at src/main/java/com/thealgorithms/maths/Area.java:84

        if (radius <= 0) {
            throw new IllegalArgumentException(POSITIVE_RADIUS);
        }
        return 4 * Math.PI * radius * radius;
    }

    /**
     * Calculate the surface area of a pyramid with a square base.
     *
     * @param sideLength side length of the square base
     * @param slantHeight slant height of the pyramid
     * @return surface area of the given pyramid
     */
    public static double surfaceAreaPyramid(final double sideLength, final double slantHeight) {
        if (sideLength <= 0) {
            throw new IllegalArgumentException("");
        }
        if (slantHeight <= 0) {
            throw new IllegalArgumentException("slant height must be greater than 0");
        }
        double baseArea = sideLength * sideLength;
        double lateralSurfaceArea = 2 * sideLength * slantHeight;
        return baseArea + lateralSurfaceArea;
    }

    /**
     * Calculate the area of a rectangle.
     *
     * @param length length of a rectangle
     * @param width  width of a rectangle
     * @return area of given rectangle
     */
    public static double surfaceAreaRectangle(final double length, final double width) {
        if (length <= 0) {
            throw new IllegalArgumentException("Length must be greater than 0");
        }
        if (width <= 0) {

View on GitHub (pinned to fdfb9a395b)

Solutions

1. Pass slantHeight > 0: surfaceAreaPyramid(4, 6).
2. Validate both pyramid arguments before the call.
3. Recompute slant height correctly (slant = sqrt((side/2)^2 + height^2)) rather than forwarding a 0.

Example fix

// before
double a = Area.surfaceAreaPyramid(side, slant);
// after
if (slant <= 0) throw new IllegalArgumentException("slant height must be > 0");
double a = Area.surfaceAreaPyramid(side, slant);

if (!(slantHeight > 0)) {
    throw new IllegalArgumentException("pyramid slant height must be > 0");
}
double a = Area.surfaceAreaPyramid(sideLength, slantHeight);

static boolean isPositiveDimension(double d) {
    return d > 0 && Double.isFinite(d);
}

try {
    double a = Area.surfaceAreaPyramid(side, slant);
} catch (IllegalArgumentException e) {
    if (e.getMessage() != null && e.getMessage().toLowerCase().contains("slant")) { /* slant offender */ }
}

When it happens

Trigger: surfaceAreaPyramid(4, 0); surfaceAreaPyramid(4, -3); a valid side paired with a zero/negative slant height.

Common situations: Slant height computed from vertical height and side that produced 0/negative via a sqrt or subtraction; default 0.0 field.

Related errors

• Side length must be greater than 0
• Length must be greater than 0
• Width must be greater than 0
• Height must be greater than 0
• Radius must be greater than 0

AI-assisted analysis of TheAlgorithms/Java@fdfb9a395b (2026-08-13). Data as JSON: /api/errors/034a76aac91db6da. Report an issue: GitHub.