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* Creating a deep vs shallow copy of an object in Java

* Creating a deep vs shallow copy of an object in Java

* Baeldung article converting number bases

* Baeldung article converting number bases

* edits made to Converting a Number from One Base to Another in Java

* added braces to oneliners

* added precondition to check input
This commit is contained in:
Iniubong LA 2023-01-19 19:03:51 +00:00 committed by GitHub
parent 1b25127d89
commit 305b369f5d
2 changed files with 42 additions and 22 deletions
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52
core-java-modules/core-java-lang-5/src/main/java/com/baeldung/convertnumberbases/ConvertNumberBases.java
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@ -2,68 +2,76 @@ package com.baeldung.convertnumberbases;
public class ConvertNumberBases { public class ConvertNumberBases {
public static String convertNumberToNewBase(String number, int base, int newBase){ public static String convertNumberToNewBase(String number, int base, int newBase) {
return Integer.toString(Integer.parseInt(number, base), newBase); return Integer.toString(Integer.parseInt(number, base), newBase);
} }
public static String convertNumberToNewBaseCustom(String num, int base, int newBase) { public static String convertNumberToNewBaseCustom(String num, int base, int newBase) {
int decimalNumber = convertFromAnyBaseToDecimal(num, base); int decimalNumber = convertFromAnyBaseToDecimal(num, base);
return convertFromDecimalToBaseX(decimalNumber, newBase); String targetBase = "";
try {
targetBase = convertFromDecimalToBaseX(decimalNumber, newBase);
} catch (IllegalArgumentException e) {
e.printStackTrace();
}
return targetBase;
} }
public static String convertFromDecimalToBaseX(int num, int newBase) { public static String convertFromDecimalToBaseX(int num, int newBase) throws IllegalArgumentException {
if ((newBase < 2 || newBase > 10) && newBase != 16) {
throw new IllegalArgumentException("New base must be from 2 - 10 or 16");
}
String result = ""; String result = "";
int remainder; int remainder;
while (num > 0) { while (num > 0) {
remainder = num % newBase; remainder = num % newBase;
if (newBase == 16) { if (newBase == 16) {
if (remainder == 10) if (remainder == 10) {
result += 'A'; result += 'A';
else if (remainder == 11) } else if (remainder == 11) {
result += 'B'; result += 'B';
else if (remainder == 12) } else if (remainder == 12) {
result += 'C'; result += 'C';
else if (remainder == 13) } else if (remainder == 13) {
result += 'D'; result += 'D';
else if (remainder == 14) } else if (remainder == 14) {
result += 'E'; result += 'E';
else if (remainder == 15) } else if (remainder == 15) {
result += 'F'; result += 'F';
else } else {
result += remainder; result += remainder;
} else }
} else {
result += remainder; result += remainder;
}
num /= newBase; num /= newBase;
} }
return new StringBuffer(result).reverse().toString(); return new StringBuffer(result).reverse().toString();
} }
public static int convertFromAnyBaseToDecimal(String num, int base) { public static int convertFromAnyBaseToDecimal(String num, int base) {
if (base < 2 || (base > 10 && base != 16)) {
if (base < 2 || (base > 10 && base != 16))
return -1; return -1;
}
int val = 0; int val = 0;
int power = 1; int power = 1;
for (int i = num.length() - 1; i >= 0; i--) { for (int i = num.length() - 1; i >= 0; i--) {
int digit = charToDecimal(num.charAt(i)); int digit = charToDecimal(num.charAt(i));
if (digit < 0 || digit >= base) {
if (digit < 0 || digit >= base)
return -1; return -1;
}
val += digit * power; val += digit * power;
power = power * base; power = power * base;
} }
return val; return val;
} }
public static int charToDecimal(char c) { public static int charToDecimal(char c) {
if (c >= '0' && c <= '9') if (c >= '0' && c <= '9') {
return (int) c - '0'; return (int) c - '0';
else } else {
return (int) c - 'A' + 10; return (int) c - 'A' + 10;
} }
}
} }

12
core-java-modules/core-java-lang-5/src/test/java/com/baeldung/convertnumberbases/ConvertNumberBasesUnitTest.java
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@ -1,5 +1,6 @@
package com.baeldung.convertnumberbases; package com.baeldung.convertnumberbases;
import static com.baeldung.convertnumberbases.ConvertNumberBases.convertFromDecimalToBaseX;
import static com.baeldung.convertnumberbases.ConvertNumberBases.convertNumberToNewBase; import static com.baeldung.convertnumberbases.ConvertNumberBases.convertNumberToNewBase;
import static com.baeldung.convertnumberbases.ConvertNumberBases.convertNumberToNewBaseCustom; import static com.baeldung.convertnumberbases.ConvertNumberBases.convertNumberToNewBaseCustom;
import static org.junit.jupiter.api.Assertions.*; import static org.junit.jupiter.api.Assertions.*;
@ -17,4 +18,15 @@ class ConvertNumberBasesUnitTest {
assertEquals(convertNumberToNewBaseCustom("11001000", 2, 8), "310"); assertEquals(convertNumberToNewBaseCustom("11001000", 2, 8), "310");
} }
@Test
void whenInputIsOutOfRange_thenIllegalArgumentExceptionIsThrown() {
Exception exception = assertThrows(IllegalArgumentException.class, ()-> {
convertFromDecimalToBaseX(100, 12);
});
String expectedMessage = "New base must be from 2 - 10 or 16";
String actualMessage = exception.getMessage();
assertTrue(actualMessage.contains(expectedMessage));
}
} }