You’re missing a couple of things here (assuming this is your full code and not just a snippet
#include <iostream> // allows you to use cout functions etc
int main() // function for your program to run
{
int startNumber = -5; // initialise variables
int endNumber = 6;
// this loops from startNumber to endNumber going up by 1 each loop
for(int i = startNumber; i <= endNumber; i++)
std::cout << i << std::endl //cout prints the value i
return 0;
}