Problem

You are given an array of student marks received on a test. Write a method to find the highest mark received on the test and return this mark.

...by students

When I learned about arrays, my professor drew out the array as a long rectangle sliced up into multiple slots. This really helped me to visualize what was in each slot of the array at any given time. I found this very helpful to keep track of the contents of the array and I continue to use drawings whenever using arrays.

Solution

Create a your method with the proper return type and accepted parameter value (array of ints).

 public static int findMax(int[] array) {

} 

Use a variable to keep track of the highest value in the array so far. At the beginning of your method, initialize this variable to 0 since we have not started looking through the array yet.

 int highest = 0; 

Use a for loop to go through each element in the array to check if it is higher than the current value saved as the highest.

 for(i = 0; i < array.length; i++) {

} 

For each element in the array, use an if statement to determine whether it is larger than the current highest variable. In order to determine this, use the '>' operator. If the current element is greater than the highest variable, you can set the highest variable to the current element in the array.

 if(array[i] > highest) {
    highest = array[i];
} 

After the for loop, return your highest variable.

 return highest; 

Putting everything together, here's what your entire method should look like:

 public static int findMax(int[] array) {
    int i; // loop iterator
    int highest = 0;

    for(i = 0; i < array.length; i++) {
        if(array[i] > highest) {
            highest = array[i];
        }
    }

    return highest;
} 

Code

Solution Code

/*
This program creates and prints out a random array of 20 marks (between 0 and 100).
It uses the findMax method to find the maximum mark and then prints out this mark.
*/

public class LinearSearchForMax {
    public static void main(String args[]) {
        int i, x;
        int highestMark;
	int[] marks = new int[20];

	// Create an array of random marks
	for(i = 0; i < marks.length; i++) {
	    marks[i] = (int)(Math.random() * 100); // generates a random number from 0-100
	    System.out.println("marks["+i+"] = " + marks[i]);
	}

	// Call your method to find the maximum mark
	highestMark = findMax(marks);

	// Display the results of your search.
	System.out.println("The highest mark is: " + highestMark);
    }

    public static int findMax(int[] array) {
        int i; // loop iterator
        int highest = 0;

        for(i = 0; i < array.length; i++) {
            if(array[i] > highest) {
                highest = array[i];
            }
        }

        return highest;
    }

}