C the greatest value in random array, not working properly - c

Question

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
int array[];
int arraySize = 460;
int max;
int array_size(int n) {
array[n];
}
int read_from_array(int n){
for(int i = 0; i <= arraySize-1;i++ )
printf("%d|",array[i]);
}
int array_generator(int n) {
for(int i = 0; i <= n; i++)
array[i] = rand() % 1000;
}
int find_max(int n) {
for(int i = 0;i <= n-1;i++)
{
if(array[i] > max)
max = array[i];
}
printf("\n%d",max);
}
int main(int argc, char** argv) {
srand(time(NULL));
array_size(arraySize);
array_generator(arraySize);
//read_from_array(arraySize);
find_max(arraySize);
return 0;
}
im learning and have made something like this to find biggest int in random array
when this variable is set < 460 it works but when i make it bigger, it wont work.
int arraySize = 460;
i want to know why this is happening and how to make it better.

Answer 1

Lots of stuff.
Firstly, your array is never actually allocated. You're putting all those random integers into... who knows where. The easy way to fix this is to put a number in the [] after the array declaration. But to do this, the size has to be a constant, so you can't use a variable like arraySize to set the size. You can use a preprocessor #define, though. Like so:
#define ARRAY_SIZE 460
int array[ARRAY_SIZE];
Your array_size function doesn't do anything.
All of your functions are declared to return an int, but there's no return statement. Either make them void or return something.
Your max should be a local variable inside find_max and it should be given a value before you try to use it in the if statement.
int find_max(int n) {
int max = array[0];
for(int i = 0;i < n;i++)
{
if(array[i] > max)
max = array[i];
}
printf("\n%d",max);
return max;
}
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
void array_init(int* array, int n) {
for(int i = 0; i < n; i++) {
array[i] = rand() % 1000;
}
}
int array_max(int* array, int n) {
int max = array[0];
for(int i = 0;i < n;i++)
{
if(array[i] > max) {
max = array[i];
}
}
return max;
}
int main(int argc, char** argv) {
srand(time(NULL));
int array_size = 460;
int array[array_size];
array_init(array, array_size);
int max = array_max(array, array_size);
printf("%d\n", max);
return 0;
}

Answer 2

max is never initialised, and may start wth a value that is larger then your array's largest value. It should be initialised thus:
#include <limits.h>
int max = INT_MIN ; // Init. to smallest possible value.