How does the binary search find the presence of an element quicker than the linear search?

Suppose x is an array of type int[] with 50 elements. Write a code segment that will count and print the frequency of number 42 in the array.

A student wrote the following code segment, intending to print 11 22 33 44:

int arr[] = {11, 22, 33, 44};
for (int i = 1; i <= 4; i++)
    System.out.println(arr[i]);

However, the program crashed with a run-time error. Can you explain the reason for this?

Write a program to input integer elements into an array of size 20 and perform the following operations:

1. Display largest number from the array
2. Display smallest number from the array
3. Display sum of all the elements of the array