No values returned from function in C - c

Question

I was trying to write a function that checks if an array has consecutive numbers (not necessarily in order), return 0 if not and 1 if yes.
For example:
24, 21, 22, 23
The return value would be 1.
22,22,22
Would return 0.
The problem is that it return 1 for something like:
22,22,22
I could really use the help looking into it.
This is the main function (no need to check it or anything, it's fine):
#include <stdio.h>
#include <stdlib.h>
/* Function declarations */
void Ex1();
void Ex2();
void Ex3();
void Ex4();
void Ex5();
/* Declarations of other functions */
int f3(int *, int);
/* ------------------------------- */
//
int main() {
int select = 0, i, all_Ex_in_loop = 0;
printf("Run menu once or cyclically?\n"
"(Once - enter 0, cyclically - enter other number) ");
if (scanf_s("%d", &all_Ex_in_loop) == 1)
do {
for (i = 1; i <= 5; i++)
printf("Ex%d--->%d\n", i, i);
printf("EXIT-->0\n");
do {
select = 0;
printf("please select 0-5 : ");
scanf_s("%d", &select);
} while ((select < 0) || (select > 5));
switch (select) {
case 1: Ex1(); break;
case 2: Ex2(); break;
case 3: Ex3(); break;
case 4: Ex4(); break;
case 5: Ex5(); break;
}
} while (all_Ex_in_loop && select);
return 0;
}
and this is the function (UPDATED):
void Ex3() {
int n, i, res;
printf("Enter the size of the Array: ");
scanf_s("%d", &n);
int *arr = (int *)malloc(n * sizeof(int));
if (!arr) {
printf("ERROR - not enough memory.");
exit(1);
}
printf("Enter an Array >>> ");
for (i = 0; i < n; i++)
scanf_s("%d", &arr[i]);
res = f3(arr, n);
printf("res = %d\n", res);
free(arr);
}
int f3(int *arr, int size) {
int i, min = arr[0], max = arr[0];
for (i = 1; i < size; i++) {
if (arr[i] < min)
min = arr[i];
if (arr[i] > max)
max = arr[i];
}
int *CounterArray = (int *)calloc(max + 1, sizeof(int));
if (!CounterArray) {
printf("ERROR - not enough memory.");
exit(1);
}
for (i = 0; i < size; i++) {
CounterArray[arr[i]]++;
}
for (i = min; i <= max; i++)
if (CounterArray[i] == 0)
return 0;
free(CounterArray);
return 1;
}

Answer 1

There are multiple problems in your code:
in function f3() you allocate an array of max + 1 integers. This would be a problem is all numbers in the array are negative. You should instead check that max - min + 1 is exactly the size of the array and allocate size elements.
you reject the array if and only if an element in the range has a 0 count. You should instead check that all elements have a 1 count. This explains why the function fails for 22,22,22.
Here is a modified version:
int f3(const int *arr, int size) {
int result = 1;
if (size <= 0)
return 1;
int i, min = arr[0], max = arr[0];
for (i = 1; i < size; i++) {
if (min > arr[i])
min = arr[i];
if (max < arr[i])
max = arr[i];
}
if (max - min + 1 != size)
return 0;
unsigned char *CounterArray = calloc(size, sizeof(*CounterArray));
if (!CounterArray) {
printf("ERROR - not enough memory.");
exit(1);
}
for (i = 0; i < size; i++) {
// increment the count of this element
if (CounterArray[arr[i] - min]++) {
// if the count was already non zero, the test fails.
result = 0;
break;
}
}
free(CounterArray);
return result;
}

Answer 2

You return zero under the condition that
if (CounterArray[i] == 0)
but in your test case of 22,22,22 you have min and max both equal 22 and CounterArray[22] equal 3, not 0.
You need to re-think the condition...