TheAlgorithms/Java · error · IllegalArgumentException

Bases must be between 2 and 10.

Error message

Bases must be between 2 and 10.

What it means

AnytoAny.convertBase() restricts both sourceBase and destBase to the range [2, 10]. Any base outside this interval (including the common bases 11-36 used for hex and beyond) is rejected. This is an intentional scope limit because digit representation beyond '9' would require letters, which this implementation does not support.

Solutions

1. For bases > 10 (hex, base32, base36), use AnyBaseToDecimal with radix up to 36, or Integer.parseInt/String.valueOf with radix.
2. Validate and clamp the base to [2,10] before calling, or reject unsupported bases earlier in your pipeline.
3. Switch to a converter that supports the extended range if your use case needs bases beyond 10.

Example fix

// before
int hex = AnytoAny.convertBase(255, 10, 16); // 16 > 10 -> throws

// after
String hex = Integer.toString(255, 16); // "ff", supports radix up to 36

if (sourceBase < 2 || sourceBase > 10 || destBase < 2 || destBase > 10) {
    throw new UnsupportedOperationException("bases outside [2,10] not supported; use Integer.parseInt with radix");
}
int result = AnytoAny.convertBase(sourceNumber, sourceBase, destBase);

static boolean basesSupportedByAnyToAny(int src, int dst) {
    return src >= 2 && src <= 10 && dst >= 2 && dst <= 10;
}

try {
    int out = AnytoAny.convertBase(n, src, dst);
} catch (IllegalArgumentException e) {
    // fall back to radix-capable converter
    out = Integer.parseInt(String.valueOf(n), src);
    // then convert via Integer.toString(out, dst)
}

When it happens

Trigger: Calling convertBase(num, 16, 10) or convertBase(num, 10, 16) to convert to/from hexadecimal. Passing base 0, 1, or a negative base. Passing base values above 10 for any radix.

Common situations: Assuming the utility handles hexadecimal (base 16). Reading base from config without clamping to the supported range. Migrating from a converter that supports bases up to 36.

Related errors

• For input string
• invalid character
• A padding '=' must not be followed by a non-padding…
• Incorrect binary digit
• Incorrect binary digit

AI-assisted analysis of TheAlgorithms/Java@fdfb9a395b (2026-08-13). Data as JSON: /api/errors/4412c35d75720172. Report an issue: GitHub.

Appendix: source

Thrown at src/main/java/com/thealgorithms/conversions/AnytoAny.java:24

 * This class provides a method to convert a source number from a given base
 * to a destination number in another base. Valid bases range from 2 to 10.
 */
public final class AnytoAny {
    private AnytoAny() {
    }

    /**
     * Converts a number from a source base to a destination base.
     *
     * @param sourceNumber The number in the source base (as an integer).
     * @param sourceBase The base of the source number (between 2 and 10).
     * @param destBase The base to which the number should be converted (between 2 and 10).
     * @throws IllegalArgumentException if the bases are not between 2 and 10.
     * @return The converted number in the destination base (as an integer).
     */
    public static int convertBase(int sourceNumber, int sourceBase, int destBase) {
        if (sourceBase < 2 || sourceBase > 10 || destBase < 2 || destBase > 10) {
            throw new IllegalArgumentException("Bases must be between 2 and 10.");
        }

        int decimalValue = toDecimal(sourceNumber, sourceBase);
        return fromDecimal(decimalValue, destBase);
    }

    /**
     * Converts a number from a given base to its decimal representation (base 10).
     *
     * @param number The number in the original base.
     * @param base The base of the given number.
     * @return The decimal representation of the number.
     */
    private static int toDecimal(int number, int base) {
        int decimalValue = 0;
        int multiplier = 1;

        while (number != 0) {

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