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Java Math.max and Math.min

This Java example page uses Math.min and Math.max to compare values and keep values in ranges. Math.min can be used with array indexes.
Math.max and min. Two numbers are different. One is larger. The other is smaller. With Math.max we get the larger one, and with Math.min we get the smaller one.
With these methods, we can restrict numbers to a valid range. We can avoid accessing an array out of range. We can keep track of the highest (or lowest) score.
First example. Here we use Math.min. We pass it two arguments and receive the argument back that is lower. We use Math.min to avoid accessing an array at an index that is too high.Arrays

Argument 1: In this example we use the last valid index of the "animals" array. We can never go higher than the last index.

Argument 2: This is the element we want to access. If this is too high, we will instead access the last valid index of the array.

Java program that uses Math.min public class Program { public static void main(String[] args) { String[] animals = { "cat", "dog", "bird" }; // Use Math.min to keep index in range. // ... Try to get index 4. String result = animals[Math.min(animals.length - 1, 4)]; System.out.println(result); // Try to get index 1. result = animals[Math.min(animals.length - 1, 1)]; System.out.println(result); } } Output bird dog
Array for-loop. In this example we have two arrays: one has 3 elements, the other 4. With Math.min we get the count of common element indexes in both arrays.

So: The Math.min method returns 3 here. Both codes1 and codes2 have 3 elements.

Finally: We print the common elements in a for-loop. The fourth element in "codes2" is not printed.

Java program that uses Math.min, arrays public class Program { public static void main(String[] args) { int[] codes1 = { 100, 200, 300 }; int[] codes2 = { 300, 400, 500, 600 }; // Use Math.min to get smallest length for both arrays. int commonLength = Math.min(codes1.length, codes2.length); // Display elements in each array at indexes. // ... All indexes have elements. for (int i = 0; i < commonLength; i++) { System.out.println(codes1[i] + "/" + codes2[i]); } } } Output 100/300 200/400 300/500
Math.max. In this example we score words based on their letters. We use Math.max to keep track of the highest-scoring word. We do not need if-statements to track this value.charAt

Tip: Often we assign a variable to the result of Math.max that is passed (as one argument) that same value.

And: This helps us modify a variable based on local maximums and minimums for Math.min.

Java program that uses Math.max public class Program { public static void main(String[] args) { String[] codes = { "abc", "def", "abcdef", "bc" }; // Loop over strings and score them on their letters. int maxScore = -1; for (String code : codes) { // Compute score for the string. int score = 0; for (int i = 0; i < code.length(); i++) { score += code.charAt(i); } System.out.println(score); // Keep track of highest score with Math.max. maxScore = Math.max(maxScore, score); } // Print highest score. System.out.println("Max score: " + maxScore); } } Output 294 303 597 197 Max score: 597
A review. With Math.max and Math.min we compare two numbers in a method call. We can avoid writing many if-statements. This leads to clearer, more correct, more declarative code.If
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