C++ Programming help

Question

You create a program that displays the sum of even integers between and including two numbers entered by the user ..

ex) 2 and 7 = the sum of 12 (2+4+6)

this is

Answer 1

You are using the same variable to control the for loop and to the sum, this won't work. Try this:

int even1 = num1 % 2 == 0 ? num1 : num1+1;
int even2 = num2 % 2 == 0 ? num2 : num2-1;
for (int i = even1; i <= even2; i += 2) sum += i;

Note that you don't really need a for loop:

int even1 = num1 % 2 == 0 ? num1 : num1+1;
int even2 = num2 % 2 == 0 ? num2 : num2-1;

// how many numbers you will sum (remember they are even, so we need to divide by 2)
int count = 1 + (even2 - even1)/2;

sum = (even1 + even2) * (count/2);
if (count % 2 == 1) sum += (even1 + even2)/2;