Wrong Random Numbers C - c

Question

I'm building a program that simulates a bus going through bus stops and picking up a random amount of passengers (0-15) the problem is that when i try to print the amount of passengers that got in on a bus stop i get a lot of numbers bigger than 15.
Here's a part of my program:
#include <stdio.h>
#include <stdlib.h>
struct Node {
int data;
struct Node* next;
};
void printList(struct Node* n)
{
while (n != NULL) {
printf(" %d ", n->data);
n = n->next;
}
}
int main()
{
struct Node*ΤΣ_ΚΤΕΛ = NULL;
struct Node*ΓΕΦΥΡΑ = NULL;
ΤΣ_ΚΤΕΛ = (struct Node*)malloc(sizeof(struct Node));
ΓΕΦΥΡΑ = (struct Node*)malloc(sizeof(struct Node));
ΤΣ_ΚΤΕΛ->data = rand()%15+1;
ΤΣ_ΚΤΕΛ->next = ΓΕΦΥΡΑ;
printList(ΓΕΦΥΡΑ);
return 0;
}

Answer 1

Below has some tweaks that fix your basic issues, with explanations in the comments:
#include <stdio.h>
#include <stdlib.h>
#include <time.h> // you should seed the rand function to get pseudorandom numbers
// each time you run
struct Node {
int data;
struct Node* next;
};
void printList(struct Node* n)
{
while (n != NULL) {
printf(" %d ", n->data);
n = n->next;
}
}
int main(void)
{
// seed the rand function with the current time, this is common
// see link below for further info
srand(time(NULL));
struct Node*ΤΣ_ΚΤΕΛ = NULL;
struct Node*ΓΕΦΥΡΑ = NULL;
ΤΣ_ΚΤΕΛ = malloc(sizeof(struct Node));
ΓΕΦΥΡΑ = malloc(sizeof(struct Node));
// always check the return value of malloc
if (ΤΣ_ΚΤΕΛ == NULL || ΓΕΦΥΡΑ == NULL)
{
// handle errors how you want
fprintf(stderr, "out of memory!\n");
exit(-1);
}
ΤΣ_ΚΤΕΛ->data = rand()%15+1;
ΤΣ_ΚΤΕΛ->next = ΓΕΦΥΡΑ;
// must fill in data for ΓΕΦΥΡΑ also
ΓΕΦΥΡΑ->data = rand()%15+1;
ΓΕΦΥΡΑ->next = NULL;
// passing in ΤΣ_ΚΤΕΛ will print both structures now
printList(ΤΣ_ΚΤΕΛ);
return 0;
}
Demonstration.
Also see:
How to generate a random int in C?
Do I cast the result of malloc?