int sum10 = 0;
for (int i = 1; i <= 10; i++) {
sum10 += i;
}
//sum10 is 55
//any step: from 0 to 6 by 2
int sumEven = 0;
for (int i = 0; i < 7; i += 2) {
sumEven += i;
}
//sumEven is 12 (0 + 2 + 4 + 6)
printf("sum10 is %d\n", sum10);
printf("sumEven is %d\n", sumEven);