Answer 1

// First, initializing an int array with 4 elements

int [ ] myArr = {6, 57, 3, 7};

// sum is a variable which will store the array sum, initializing it with 0.
// why 0? because 0 will not affect the actual total sum

int sum=0;

// The main part

/*

Think about the sum calculation without a loop. What should you do then? You'll have to add all the array elements with initial sum, right?

Calculating without loop:
sum = sum+ myArr[0] // sum = 0+6 = 6
sum = sum+ myArr[1] // sum = 6+57 = 63
sum = sum+ myArr[2] // sum = 63+3 = 66
sum = sum+ myArr[3] // sum = 66+7 = 73
Note, for array of size 4, the valid indices are 0,1,2,3. (Not 4, it's a common mistake)

Now, come back to loop. From the above calculation we can see that we are getting a common pattern each time:
sum = sum + myArr[index which differs];
So we can write a loop which will iterate over the index value.

What should be the starting index? 0
What should be the end-condition? upto index 3 or upto myArr.length-1
The index changes like 0,1,2,3... so it should be incremented after each iteration

We are expressing the common index as x inside the loop

*/
for(int x=0; x<myArr.length; x++) {
sum += myArr[x];
// sum += myArr[x] is same as sum=sum+myArr[x]
}
// done with loop, now print the final sum
System.out.println(sum);

// DONE!! :)