Question

1. Write a loop for each of the following:
   1. The sum of all even numbers between 2 and 100 (inclusive).

2. The sum of all squares between 1 and 100 (inclusive). (If you use the pow function the first parameter must be a float or double).

3. The sum of all odd numbers between a and b (inclusive). Where a and b are read in by the user.

2. How often do the following loops execute? Assume that i is not changed in the loop body.
   1. for (int i = 1; i <= 10; i++) . . .
   2. for (int i = 0; i < 10; i++) . . .
   3. for (int i = 10; i > 0; i--) . . .
   4. for (int i = -10; i <= 10; i++) . . .
   5. for (int i = -10; i <= 10; i = i + 2) . . .

Help, please!

Answer 1

a)

int sum = 0;

for(int i =2;i<=100;i+=2) {
           sum+=i;
       }

b)

int sum = 0;

for (int i = 1; i <= 100; i += 1) {
           sum += i * i;
       }

c)

Scanner scan = new Scanner(System.in);
       int sum = 0;

// Take input
       int a = scan.nextInt();
       int b = scan.nextInt();
      
       // Iterate loop from a to b
       for (int i = a; i <= b; i++) {
           // If number is not divisible by 2 means it's odd
           // Add it to sum
           if (i % 2 != 0) {
               sum += i;
           }
       }

a)

This loop will run 10 times from 1 to 10

b)

This loop will run 10 times from 0 to 9

c)

This loop will run 10 times from 10 to 1

d)

This loop will run 21 times from -10, -9,-8......,-1,0,1,2.....,10

e)

This loop will run 11 times from -10, -8, -6, -4, -2, 0, 2, 4, 6, 8, 10