Day 12 Recap Questions
  1. What output is printed by the “Example code” below?
  2. Assume that arr is an array of 5 int elements. Is the code int *p = arr + 5; legal?
  3. Assume that arr is an array of 5 int elements. Is the code int *p = arr + 5; printf("%d\n", *p); legal?
  4. What output is printed by the “Example code 2” below?
  5. Suppose we have variables int ra1[10] = { 1, 2, 3};, int * ra2 = ra1; and int fun(int *ra); declarations. Will fun(ra1); compile? Will fun(ra2); compile? What if we change the function declaration to int fun(const int ra[]);?
// Example code
int arr[] = { 94, 69, 35, 72, 9 };
int *p = arr;
int *q = p + 3;
int *r = q - 1;
printf("%d %d %d\n", *p, *q, *r);
ptrdiff_t x = q - p;
ptrdiff_t y = r - p;
ptrdiff_t z = q - r;
printf("%d %d %d\n", (int)x, (int)y, (int)z);
ptrdiff_t m = p - q;
printf("%d\n", (int)m);
int c = (p < q);
int d = (q < p);
printf("%d %d\n", c, d);

// Example code 2

#include <stdio.h>

int sum(int a[], int n) {
  int x = 0;
  for (int i = 0; i < n; i++) {
    x += a[i];
  }
  return x;
}

int main(void) {
  int data[] = { 23, 59, 82, 42, 67, 89, 76, 44, 85, 81 };
  int result = sum(data + 3, 4);
  printf("result=%d\n", result);
  return 0;
}