Preface: a previous blog Address book dynamic version In, I have completed an address book that can dynamically increase the capacity. When the address book runs, you can add and delete data to the address book. At this time, the data is stored in memory, but when the program exits, we will find that the data in the address book does not exist. When the address book program runs next time, the data will have to be re entered, Such an address book will inevitably have a lot of trouble. Therefore, in order to solve this problem, this time we will bring the address book version 2.0, that is, the version that can be saved in a file. Next, let's have a look!
stay One time can learn the file operation! Introduced many file operations, which will be used to optimize our address book this time.
Save address book data to file
In order to ensure that the address book still has the data entered for the first time when it is opened for the second time, we need to save the data in the address book to the file before closing the address book for the first time, so we define a function SaveContact to save the data to the file, which is defined as:
void SaveContact(Contact* pc)
{
FILE* pf = fopen("Contact.dat", "w");//Create and open a file as a write
if (pf == NULL)
{
perror("Contact.dat");
return;
}
int i = 0;
for (i = 0; i < pc->sz; i++)
{
fwrite(pc->data + i, sizeof(PeoInfo), 1, pf);//Saving data to a file using a loop
}
fclose(pf);
pf = NULL;
}
Load data into address book
When we save the data of the last address book, the next time we use the address book, we should first load the data saved in the last address book into the address book, so we need to adjust the function of initializing the address book accordingly, that is, load the data first during initialization, and the defined function is LoadContact, It should also be noted that during data loading, if the loaded data capacity is greater than the original capacity, the loading will fail. In order to avoid this situation, it is necessary to judge whether the capacity needs to be expanded before loading, so the function CheckCapacity is defined to judge.
The two functions are as follows:
void CheckCapacity(Contact* pc)
{
if (pc->sz == pc->capacity)
{
PeoInfo* ptr = (PeoInfo*)realloc(pc->data, (ADD_CAP + pc->capacity) * sizeof(PeoInfo));
if (ptr != NULL)
{
pc->data = ptr;
pc->capacity += ADD_CAP;
printf("Successful capacity increase!\n");
}
else
{
printf("Capacity increase failed\n");
return;
}
}
}
void LoadContact(Contact * pc)
{
FILE* pf = fopen("Contact.dat", "r");//Open file read
if (pf == NULL)
{
perror("Contact.dat");
return;
}
PeoInfo tmp = { 0 };
while (fread(&tmp, sizeof(PeoInfo), 1, pf))//Load one data into the address book at a time when the data in the address book is added
//After loading and playing, the fread function will return 0. At this time, the loop will end naturally
{
CheckCapacity(pc);//Before loading, first judge whether to expand the capacity
pc->data[pc->sz] = tmp;
pc->sz++;
}
fclose(pf);
pf = NULL;
}
Code overview
The same is divided into three documents as follows:
contact.h
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#define MAX_NAME 20
#define SEX 10
#define MAX_ADDR 100
#define MAX_TELE 12
#define MAX_SZ 3
#define ADD_CAP 2
#define MAX 1000
typedef struct PeoInfo
{
char name[MAX_NAME];
char sex[SEX];
int age;
char tele[MAX_TELE];
char addr[MAX_ADDR];
} PeoInfo; //Redefine for ease of use, the same below
typedef struct Contact
{
PeoInfo* data;
int sz;
int capacity;
}Contact; //redefinition
void InitContact(Contact* pc); //Initialize address book
void AddContact(Contact* pc); //Add a contact
void PrintContact(const Contact* pc); //Print address book
void DelContact(Contact* pc); //Delete Contact
void SearchContact(Contact* pc); //find contact
void ModifyContact(Contact* pc); //Modify contact
void DestoryContact(Contact* pc); //Destroy address book
void SaveContact(Contact* pc); //Save address book
void LoadContact(Contact* pc); //Load address book
void CheckCapacity(Contact* pc); //Determine address book
test.c
#include"contact.h" / / reference header file
void menu()
{
printf("***************************\n");
printf("*** 1.Add 2.Del ***\n");
printf("*** 3.Search 4.Modify***\n");
printf("*** 5.Print ***\n");
printf("*** 0.Exit ***\n");
printf("***************************\n");
}
enum Option //Define the name of each function as a member of an enumeration type to make it more recognizable
{
EXIT,
ADD,
DEL,
SEARCH,
MODIFY,
PRINT,
};
int main()
{
Contact con;
InitContact(&con);
int input = 0;
do
{
menu();
scanf("%d", &input);
switch (input)
{
case ADD:
AddContact(&con);//Add a Contact
break;
case DEL:
DelContact(&con);//Delete Contact
break;
case SEARCH:
SearchContact(&con);//find contact
break;
case MODIFY:
ModifyContact(&con);//Modify contact
break;
case PRINT:
PrintContact(&con);//show address book
break;
case EXIT:
SaveContact(&con);//Save the data in the address book before destroying it
DestoryContact(&con);//Destroy address book
printf("Exit address book\n");
break;
default:
printf("Selection error, please re select:");
break;
}
} while (input);
return 0;
}
contact.c
#include"contact.h"
void CheckCapacity(Contact* pc)
{
if (pc->sz == pc->capacity)
{
PeoInfo* ptr = (PeoInfo*)realloc(pc->data, (ADD_CAP + pc->capacity) * sizeof(PeoInfo));
if (ptr != NULL)
{
pc->data = ptr;
pc->capacity += ADD_CAP;
printf("Successful capacity increase!\n");
}
else
{
printf("Capacity increase failed\n");
return;
}
}
}
void LoadContact(Contact * pc)
{
FILE* pf = fopen("Contact.dat", "r");
if (pf == NULL)
{
perror("Contact.dat");
return;
}
PeoInfo tmp = { 0 };
while (fread(&tmp, sizeof(PeoInfo), 1, pf))
{
CheckCapacity(pc);
pc->data[pc->sz] = tmp;
pc->sz++;
}
fclose(pf);
pf = NULL;
}
void InitContact(Contact* pc)
{
pc->data = (PeoInfo*)malloc(MAX_SZ * sizeof(PeoInfo));
if (pc->data == NULL)
{
perror("InitContact");
return;
}
pc->sz = 0;
pc->capacity = MAX_SZ;
LoadContact(pc);
}
void DestoryContact(Contact* pc)
{
free(pc->data);
pc->data = NULL;
pc->sz = 0;
pc->capacity = 0;
}
//Save address book
void SaveContact(Contact* pc)
{
FILE* pf = fopen("Contact.dat", "w");
if (pf == NULL)
{
perror("Contact.dat");
return;
}
int i = 0;
for (i = 0; i < pc->sz; i++)
{
fwrite(pc->data + i, sizeof(PeoInfo), 1, pf);
}
fclose(pf);
pf = NULL;
}
void AddContact(Contact* pc)
{
CheckCapacity(pc);
printf("Please enter your name:>");
scanf("%s", pc->data[pc->sz].name);
printf("Please enter gender:>");
scanf("%s", pc->data[pc->sz].sex);
printf("Please enter age:>");
scanf("%d", &(pc->data[pc->sz].age));
printf("Please enter phone number:>");
scanf("%s", pc->data[pc->sz].tele);
printf("Please enter the address:>");
scanf("%s", pc->data[pc->sz].addr);
pc->sz++;
printf("Increase success!\n");
}
void PrintContact(const Contact* pc)
{
printf("%-20s\t%-5s\t%-5s\t%-12s\t%-20s\t\n", "full name", "Gender", "Age", "Telephone", "address");
int i = 0;
for (i = 0; i < pc->sz; i++)
{
printf("%-20s\t%-5s\t%-5d\t%-12s\t%-20s\t\n",
pc->data[i].name,
pc->data[i].sex,
pc->data[i].age,
pc->data[i].tele,
pc->data[i].addr);
}
}
static int FindContact(const Contact* pc, char name[])
{
int i = 0;
for (i = 0; i < pc->sz; i++)
{
if (strcmp(name, (pc->data[i]).name) == 0)
return i;
}
return -1;
}
void DelContact(Contact* pc)
{
char name[MAX_NAME] = { 0 };
printf("Please enter the contact to delete:>");
scanf("%s", name);
int x = FindContact(pc, name);
if (x < 0)
{
printf("No contacts found\n");
}
else
{
int i = 0;
for (i = x; x < pc->sz - 1; x++)
{
pc->data[x] = pc->data[x + 1];
}
pc->sz--;
printf("Delete succeeded!\n");
}
}
void SearchContact(Contact* pc)
{
char name[MAX_NAME] = { 0 };
printf("Please enter the contact you want to find:>");
scanf("%s", name);
int x = FindContact(pc, name);
if (x < 0)
{
printf("No contacts found\n");
}
else
{
printf("%-20s\t%-5s\t%-5s\t%-12s\t%-20s\t\n", "full name", "Gender", "Age", "Telephone", "address");
printf("%-20s\t%-5s\t%-5d\t%-12s\t%-20s\t\n",
pc->data[x].name,
pc->data[x].sex,
pc->data[x].age,
pc->data[x].tele,
pc->data[x].addr);
}
}
void ModifyContact(Contact* pc)
{
char name[MAX_NAME] = { 0 };
printf("Please enter the contact to modify:>");
scanf("%s", name);
int x = FindContact(pc, name);
if (x < 0)
{
printf("No contacts found\n");
}
else
{
printf("Please enter your name:>");
scanf("%s", pc->data[x].name);
printf("Please enter gender:>");
scanf("%s", pc->data[x].sex);
printf("Please enter age:>");
scanf("%d", &(pc->data[x].age));
printf("Please enter phone number:>");
scanf("%s", pc->data[x].tele);
printf("Please enter the address:>");
scanf("%s", pc->data[x].addr);
printf("Modified successfully!\n");
}
}