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Add unit tests for ParseInteger (#4228)

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This commit is contained in:
Albina Gimaletdinova
2023-07-02 11:31:55 +03:00
committed by GitHub
parent 4b45ac7e71
commit 2456d86432
3 changed files with 48 additions and 11 deletions
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14
src/main/java/com/thealgorithms/maths/ParseInteger.java
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@ -1,32 +1,24 @@
package com.thealgorithms.maths;
public class ParseInteger {
public static void main(String[] args) {
assert parseInt("123") == Integer.parseInt("123");
assert parseInt("-123") == Integer.parseInt("-123");
assert parseInt("0123") == Integer.parseInt("0123");
assert parseInt("+123") == Integer.parseInt("+123");
}
/**
* Parse a string to integer
*
* @param s the string
* @return the integer value represented by the argument in decimal.
* @throws NumberFormatException if the {@code string} does not contain a
* parsable integer.
* parsable integer.
*/
public static int parseInt(String s) {
if (s == null || s.length() == 0) {
throw new NumberFormatException("null");
throw new NumberFormatException("Input parameter must not be null!");
}
boolean isNegative = s.charAt(0) == '-';
boolean isPositive = s.charAt(0) == '+';
int number = 0;
for (int i = isNegative ? 1 : isPositive ? 1 : 0, length = s.length(); i < length; ++i) {
if (!Character.isDigit(s.charAt(i))) {
throw new NumberFormatException("s=" + s);
throw new NumberFormatException("Input parameter of incorrect format: " + s);
}
number = number * 10 + s.charAt(i) - '0';
}