Code going into infinite loop, not sure why - c++

Question

I'm in an introductory c++ course, and am having trouble with this prompt:
"Write a loop that reads positive integers from standard input and that terminates when it reads an integer that is not positive. After the loop terminates, it prints out the sum of all the even integers read, the sum of all the odd integers read, a count of the number of even integers read, and a count of the number of odd integers read, all separated by exactly one space. Declare any variables that are needed."
My solution is as follows:
int num = 0;
int evens = 0;
int odds = 0;
int evenSum = 0;
int oddSum = 0;
do {
cin >> num;
if (num % 2 == 0){
evens++;
evenSum += num;
}
else if (num > 0) {
odds++;
oddSum += num;
}
else {
num = -1;
}
}
while (num >= 0);
cout << evenSum << " " << oddSum << " " << evens << " " << odds;
I get no feedback except "Failure: code goes into infinite loop" from the autograder. What am I doing wrong?

Answer 1

You are also processing negative numbers in this if (num % 2 == 0) part(example: this condition when encountered for first negative integer will also be true e.g -6), thereby incrementing evens and adding this negative number to evenSum, which shoudln't have been done as per your question's requirement; Other thing is that the else part is not necessary, I mean why assign -1 to num instead letting it stay the same number you just read(as it is not in your question's requirement).
I think your else if and else part needs to be changed like this:
#include <iostream>
using namespace std;
int main(){
int num;
int evens = 0;
int odds = 0;
int evenSum = 0;
int oddSum = 0;
while (true) {
cin >> num;
if (num < 0){
break;
}
if (num % 2 == 0){
evens++;
evenSum += num;
}
else {
odds++;
oddSum += num;
}
}
cout << evenSum << " " << oddSum << " " << evens << " " << odds;
return 0;
}
Keep taking the numbers from input, if num < 0 then break and show the results, else check for the number being either odd or even and increment the counters accordingly.

Answer 2

You never make num positive in your loop. All your doing is changing other variables. Also you don't need to reassign num to -1 if it's already negative.
You need to add this:
else if (num > 0) {
odds++;
oddSum += num;
num = 1; //becomes positive and breaks the loop.
}

Answer 3

The while part of your loop will keep going until a negative answer is put in. Where are you getting your num from? User input? Your declaration has made it 0, which is making your while loop continue since the condition is >=. If you want user input there should be a cout statement proceeding your cin.