You do not need to store prev
pointer since there is no need for it. Remove prev variable and go on.
Change the algorithm to return 1 if the number is found and return 0 if it is not found. prev pointer is useless.
Here is the code.
int list_search_number(LinkedListNode head, Client value){
LinkedListNode curr;
curr = head;
while (curr != NULL) {
if(curr->value.number==value.number){
return 1;
}
else {
curr = curr->next;
}
}
return 0;
}