Question

I have the following exercise program from a book. The book states that for values x=10 and y=100, functions; min, max, incr and square are called 1, 91, 90 and 90 respectively. However, to me it looks like they are being called the following number of times, 1, 1, 1 and 0. Can someone explain to me the book numbers. Thanks.

#include <stdio.h>

int min(int x, int y){
    return x < y ? x : y;
}

int max(int x, int y){
    return x > y ? y : x;
}

void incr(int *xp, int v) {
    *xp += v;
}

int square (int x){
    return x*x;
}

int main(void){
    int i;
    int x = 10;
    int y = 100;
    int t = 0;

    for (i = min(x, y); i < max(x, y); incr(&i, 1)){
        t += square(i);
        printf("test %i", t);
    }
}

Answer 1

Well the loop is really (as x and y don’t change):

for (i = 10; i < 100; incr(&i, 1))

The the first statement executes only once – that’s why min is executed 1 time.
The stop condition is executed once at the beginning and then after each iteration – so 91 times. The third statemnt is executed at the end of each iteration – so 90 times.

So the book is correct.