Merge pull request #39 from Pasqualecoder/main

add 4.c chapter 14

.gitignore

@@ -3,4 +3,5 @@
 *.out
 *.so
 /.vscode
-/output
+/output
+Programming in ANSI C (E Balagurusamy) (Z-Library).pdf

solutions/Pasquale/14/4.c

@@ -0,0 +1,148 @@
+
+// ---------- list.h -------------------
+typedef struct customer_tag {
+    char name[15];
+    char phone[15];
+} customer;
+
+void print_customer(customer *c);
+customer input_customer();
+
+
+typedef struct node_tag {
+    customer customer;
+    struct node_tag *next;
+} node;
+typedef node *list;
+
+list new_list();
+void print_list(list l);
+void insert_list(list *l);
+void delete_list(list *l, int index);
+// ------------------------------------
+
+// ----------- list.c -----------------
+#include <stdio.h>
+#include <stdlib.h>
+
+void print_customer(customer *c) {
+    printf("Name: %s\n", c->name);   
+    printf("phone: %s\n\n", c->phone);   
+}
+
+customer input_customer() {
+    customer c;
+    printf("Insert the name: ");
+    scanf("%s", c.name);
+    printf("Insert the phone number: ");
+    scanf("%s", c.phone);
+    return c;
+}
+
+
+list new_list() {
+    return (list) malloc(sizeof(node));
+}
+
+void print_list(list l) {
+    if (l == NULL) {
+        printf("The customer list is empty\n");
+        return;
+    }
+    for (int i = 1; l != NULL; i++)
+    {
+        printf("Customer #%d:\n", i);
+        print_customer(&l->customer);
+        l = l->next;
+    }
+}
+
+void insert_list(list *l) {
+    if (*l == NULL) {
+        *l = new_list();
+        (*l)->customer = input_customer();
+        (*l)->next = NULL;
+        return;
+    }
+    else {
+        list copy = *l;
+        while (copy->next != NULL) {
+            copy = copy->next;
+        }
+
+        list last = new_list();
+        last->customer = input_customer();
+        last->next = NULL;
+
+        copy->next = last;
+    }
+}
+
+void delete_list(list *l, int index) {
+    if (index == 0) {
+        list tmp = *l;
+        (*l) = (*l)->next;
+        free(tmp);
+        printf("User deleted\n");
+        return;
+    }
+
+    list actual = *l;
+    list prec;
+    int i;
+    for (i = 0; i < index && actual->next != NULL; i++) {
+        prec = actual;
+        actual = actual->next;
+    }
+    if (i == index) {
+        prec->next = actual->next;
+        free(actual);
+        printf("User deleted\n");
+    } 
+    else {
+        printf("User doesn't exist\n");
+    }
+}
+// ------------------------------------
+
+
+// ------------ main.c ----------------
+#include <stdio.h>
+#include <stdlib.h>
+// #include "list.h"
+
+int main() {
+    list customers = NULL;
+    int operation;
+
+    printf("Welcome\n");
+    do {
+        printf("1. Print all customers\n");
+        printf("2. Add customer\n");
+        printf("3. Delete customer\n");
+        printf("0. Exit\n>");
+        scanf("%d", &operation); getchar();
+
+        switch (operation)
+        {
+        case 1:
+            print_list(customers);
+            break;
+        case 2:
+            insert_list(&customers);
+            break;
+        case 3:
+            int index;
+            printf("Insert the number of the customer to be deleted: ");
+            scanf("%d", &index); index--;
+            delete_list(&customers, index);
+            break;
+        default:
+            operation = 0;
+            break;
+        }
+    } while (operation);
+    printf("Bye\n");
+
+    return 0;
+}