A for loop adding up a total

A for loop runs its body once per value of the counter. Watch i go 1, 2, 3, 4 and total grow each time the body runs.

Notice the jump back up to the for line after each pass: that's where i++ happens and the condition i <= 4 is checked again. When it's false, the loop ends and i disappears, because it only exists inside the loop.

#include <stdio.h>

int main(void) {
    int total = 0;
    for (int i = 1; i <= 4; i++) {
        total += i;
    }
    printf("total = %d\n", total);
    return 0;
}

Output:

total = 10

From the lesson: Loops