refactor: DecimalToAnyBase (#5343)

This commit is contained in:
Alex Klymenko
2024-08-18 20:45:30 +02:00
committed by GitHub
parent 404ad7272f
commit 2905ccbb20
2 changed files with 69 additions and 46 deletions

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@ -1,69 +1,69 @@
package com.thealgorithms.conversions;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
/**
* Class that provides methods to convert a decimal number to a string representation
* in any specified base between 2 and 36.
*
* @author Varun Upadhyay (<a href="https://github.com/varunu28">...</a>)
*/
// Driver Program
public final class DecimalToAnyBase {
private static final int MIN_BASE = 2;
private static final int MAX_BASE = 36;
private static final char ZERO_CHAR = '0';
private static final char A_CHAR = 'A';
private static final int DIGIT_OFFSET = 10;
private DecimalToAnyBase() {
}
public static void main(String[] args) throws Exception {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
System.out.println("Enter the decimal input below: ");
int decInput = Integer.parseInt(br.readLine());
System.out.println();
/**
* Converts a decimal number to a string representation in the specified base.
* For example, converting the decimal number 10 to base 2 would return "1010".
*
* @param decimal the decimal number to convert
* @param base the base to convert to (must be between {@value #MIN_BASE} and {@value #MAX_BASE})
* @return the string representation of the number in the specified base
* @throws IllegalArgumentException if the base is out of the supported range
*/
public static String convertToAnyBase(int decimal, int base) {
if (base < MIN_BASE || base > MAX_BASE) {
throw new IllegalArgumentException("Base must be between " + MIN_BASE + " and " + MAX_BASE);
}
System.out.println("Enter the base below: ");
int base = Integer.parseInt(br.readLine());
System.out.println();
if (decimal == 0) {
return String.valueOf(ZERO_CHAR);
}
System.out.println("Decimal Input"
+ " is: " + decInput);
System.out.println("Value of " + decInput + " in base " + base + " is: " + convertToAnyBase(decInput, base));
List<Character> digits = new ArrayList<>();
while (decimal > 0) {
digits.add(convertToChar(decimal % base));
decimal /= base;
}
br.close();
StringBuilder result = new StringBuilder(digits.size());
for (int i = digits.size() - 1; i >= 0; i--) {
result.append(digits.get(i));
}
return result.toString();
}
/**
* This method produces a String value of any given input decimal in any
* base
* Converts an integer value to its corresponding character in the specified base.
* This method is used to convert values from 0 to 35 into their appropriate character representation.
* For example, 0-9 are represented as '0'-'9', and 10-35 are represented as 'A'-'Z'.
*
* @param inp Decimal of which we need the value in base in String format
* @return string format of the converted value in the given base
* @param value the integer value to convert (should be less than the base value)
* @return the character representing the value in the specified base
*/
public static String convertToAnyBase(int inp, int base) {
ArrayList<Character> charArr = new ArrayList<>();
while (inp > 0) {
charArr.add(reVal(inp % base));
inp /= base;
}
StringBuilder str = new StringBuilder(charArr.size());
for (Character ch : charArr) {
str.append(ch);
}
return str.reverse().toString();
}
/**
* This method produces character value of the input integer and returns it
*
* @param num integer of which we need the character value of
* @return character value of input integer
*/
public static char reVal(int num) {
if (num >= 0 && num <= 9) {
return (char) (num + '0');
private static char convertToChar(int value) {
if (value >= 0 && value <= 9) {
return (char) (ZERO_CHAR + value);
} else {
return (char) (num - 10 + 'A');
return (char) (A_CHAR + value - DIGIT_OFFSET);
}
}
}

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package com.thealgorithms.conversions;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertThrows;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.CsvSource;
public class DecimalToAnyBaseTest {
@ParameterizedTest
@CsvSource({"0, 2, 0", "0, 16, 0", "0, 36, 0", "10, 2, 1010", "255, 16, FF", "100, 8, 144", "42, 2, 101010", "1234, 16, 4D2", "1234, 36, YA"})
void testConvertToAnyBase(int decimal, int base, String expected) {
assertEquals(expected, DecimalToAnyBase.convertToAnyBase(decimal, base));
}
@Test
void testBaseOutOfRange() {
assertThrows(IllegalArgumentException.class, () -> DecimalToAnyBase.convertToAnyBase(10, 1));
assertThrows(IllegalArgumentException.class, () -> DecimalToAnyBase.convertToAnyBase(10, 37));
}
}