Müşteri Değerlendirme Sistemi

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdlib.h>

typedef struct Node {
    int userID;
    int itemID;
    float rating;
    struct Node* next;
} Node;

Node* head = NULL;

void insert(int userID, int itemID, float rating) {
    Node* curr = head;
    while (curr != NULL) {
        if (curr->userID == userID && curr->itemID == itemID) {
            curr->rating = rating;
            printf("Customer rating (%d, %d) is updated\n", userID, itemID);
            return;
        }
        curr = curr->next;
    }
    Node* newNode = (Node*)malloc(sizeof(Node));
    newNode->userID = userID;
    newNode->itemID = itemID;
    newNode->rating = rating;
    newNode->next = head;
    head = newNode;
    printf("Customer rating (%d, %d) is added successful\n", userID, itemID);
}

void removeRating(int userID, int itemID) {
    Node* curr = head;
    Node* prev = NULL;
    while (curr != NULL) {
        if (curr->userID == userID && curr->itemID == itemID) {
            if (prev == NULL) {
                head = curr->next;
            }
            else {
                prev->next = curr->next;
            }
            free(curr);
            printf("Customer rating (%d, %d) is removed successful\n", userID, itemID);
            return;
        }
        prev = curr;
        curr = curr->next;
    }
    printf("Customer rating (%d, %d) does not exist\n", userID, itemID);
}

void rating(int userID, int itemID) {
    Node* curr = head;
    while (curr != NULL) {
        if (curr->userID == userID && curr->itemID == itemID) {
            printf("Customer rating (%d, %d) is: %0.1f\n", userID, itemID, curr->rating);
            return;
        }
        curr = curr->next;
    }
    printf("Customer rating (%d, %d) is: 0.0\n", userID, itemID);
}

void average(int itemID) {
    Node* current = head;
    int number = 0;
    float sum = 0.0;
    while (current != NULL) {
        if (current->itemID == itemID) {
            number++;
            sum += current->rating;
        }
        current = current->next;
    }
    if (number == 0) {
        printf("Average rating (%d) is: 0.0\n", itemID);
    }
    else {
        printf("Average rating (%d) is: %0.1f\n", itemID, sum / number);
    }
}

int main() {
    char remark[10];
    int userID, itemID;
    float ratingValue;
    while (scanf("%s", remark) != EOF) {
        if (strcmp(remark, "INSERT") == 0) {
            scanf("%d %d %f", &userID, &itemID, &ratingValue);
            insert(userID, itemID, ratingValue);
        }
        else if (strcmp(remark, "REMOVE") == 0) {
            scanf("%d %d", &userID, &itemID);
            removeRating(userID, itemID);
        }
        else if (strcmp(remark, "RATING") == 0)
        {
            scanf("%d %d", &userID, &itemID);
            rating(userID, itemID);
        }
        else if (strcmp(remark, "AVERAGE") == 0) {
            scanf("%d", &itemID);
            average(itemID);
        }
    }
    return 0;
}