Realize a binary read-write address book

results

1. A binary read-write address book , After each procedure , The entered information will be saved to the folder where the current project is located （ Of course, the path can be changed ）
2. The written address book is in binary form , So if it is not read in binary , I can't understand the contents
3. Integrate knowledge points ： Structure , Dynamic memory allocation , Callback function , Classification of methods , The pointer , Document reading and writing, etc .

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Implementation steps

1. The header file defines some identifier constants and header files , Of course, the types commonly used in programs can also be written here , For example, the personal information in the following code （ Structure ） And contacts （ Nested structure ）, Of course, the most important thing is the function declaration
2. Define two source files respectively , It is used for the specific implementation of each function and the final function test
3. In fact, we can first implement the static version of the address book （ Dynamic memory development is not involved ）, Then optimize it into a dynamic version （ First of all ： There is no longer an upper limit on the number of contacts , Secondly, space can be fully utilized ）, Finally, the reading and writing of the composition makes the contact information persistent .

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Code

//contact.h
#pragma once
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define NAME_MAX 10
#define SEX_MAX 5
#define TEL_MAX 15
#define ADDR_MAX 30
#define DEFAULT_SZ 3
#define INCREASED_SZ 2
// Personal information 
struct PeopInfo
{
    
	char name[NAME_MAX];
	int age;
	char sex[SEX_MAX];
	char tel[TEL_MAX];
	char addr[ADDR_MAX];
};
// The whole address book 
struct contact
{
    
	struct PeopInfo* data;
	int sz;// Record the number of valid data 
	int capacity;// Record the maximum capacity of the current address book 
};
// Initialize address book 
void initContact(struct contact* pc);
// Add a Contact 
void AddContact(struct contact* pc);
// Print address book 
void ShowContact(struct contact* pc);
// Delete Contact （ By name ）
void DelContact(struct contact* pc);
// Find contacts （ By name ）, And print 
void SearchContact(struct contact* pc);
// Modify contact information 
void ModifyContact(struct contact* pc);
// Destroy the address book 
void DestoryContact(struct contact* pc);
// Sort by age 
void SortContact(struct contact* pc);
// Save the address book information to the file 
void SaveContact(struct contact* pc);
// Load address book information 
void LoadContact(struct contact* pc);
// Check the capacity 
void CheckCapacity(struct contact* pc);

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//contact.c
#include "contact.h"
// Check the capacity 
void CheckCapacity(struct contact* pc)
{
    
	if (pc->sz == pc->capacity)
	{
    
		// The data is full , Increase capacity 
		struct PeopInfo* tmp = (struct PeopInfo*)realloc(pc->data, (2 + pc->capacity) * sizeof(struct PeopInfo));// Expand two 
		if (tmp != NULL)
		{
    
			pc->data = tmp;
			// Successful expansion , And the capacity increased each time is defaulted to 2 individual 
			pc->capacity += 2;
			//printf(" Successful expansion ！\n");
		}
		else
		{
    
			perror(" Address book capacity increase failed ");
			exit(1);
		}
	}
}
// Load address book information 
void LoadContact(struct contact* pc)
{
    
	FILE* pf = fopen("contact.txt", "rb");
	if (pf == NULL)
	{
    
		perror("LoadContact::fopen");
		return;
	}
	struct PeopInfo tmp = {
     0 };
	while (fread(&tmp, sizeof(struct PeopInfo), 1, pf))// Read one at a time 
	{
    
		// If the space is not enough, you need to increase the space 
		CheckCapacity(pc);
		pc->data[pc->sz] = tmp;
		pc->sz++;
	}
	fclose(pf);
	pf = NULL;
}
// Initialize address book 
void initContact(struct contact* pc)
{
    
	pc->sz = 0;// At first, there was no data 
	pc->data = (struct PeopInfo*)malloc(DEFAULT_SZ * sizeof(struct PeopInfo));// By default, three spaces are initialized to store information 
	pc->capacity = DEFAULT_SZ;// That is, the default initialization capacity 

	// Load the information in the file into the address book 
	LoadContact(pc);
}
// Find the specified contact by name 
int FindByName(struct contact* pc, char* name)
{
    
	int ret = -1;
	for (int i = 0; i < pc->sz; i++)
	{
    
		if (strcmp(name, pc->data[i].name) == 0)
		{
    
			ret = i;
			break;
		}
	}
	return ret;
}
// Add a Contact 
void AddContact(struct contact* pc)
{
    

	CheckCapacity(pc);
	struct PeopInfo tmp = {
     0 };
	printf(" Please enter a name ：");
	scanf("%s", tmp.name);
	printf(" Please enter age ：");
	scanf("%d", &(tmp.age));
	printf(" Please enter gender ：");
	scanf("%s", tmp.sex);
	printf(" Please input the phone number ：");
	scanf("%s", tmp.tel);
	printf(" Please enter the address :");
	scanf("%s", tmp.addr);

	pc->data[pc->sz] = tmp;
	pc->sz++;

	printf(" Contact added successfully ！\n");
}

// Print address book 
void ShowContact(struct contact* pc)
{
    
	if (pc->sz == 0)
	{
    
		printf(" Address book is empty ！\n");
		return;
	}
	// When the address book is not empty 
	printf("%-5s\t%-5s\t%-5s\t%-15s\t\t%-20s\n", " full name ", " Age ", " Gender ", " Telephone ", " Address ");
	for (int i = 0; i < pc->sz; i++)
	{
    
		printf("%-5s\t%-5d\t%-5s\t%-15s\t\t%-20s\n", pc->data[i].name,
			pc->data[i].age,pc->data[i].sex,pc->data[i].tel,pc->data[i].addr);
	}
}
// Delete the specified contact 
void DelContact(struct contact* pc)
{
    
	char name[NAME_MAX];
	printf(" Please enter the contact name to be deleted ：");
	scanf("%s", name);
	int ret = FindByName(pc, name);
	if (ret == -1)
	{
    
		printf(" Check no one ！\n");
		return;
	}
	for (int i = ret; i < pc->sz-1; i++)
	{
    
		pc->data[i] = pc->data[i + 1];// The next data overwrites the previous data 
	}
	pc->sz--;
	printf(" Delete contact successfully ！\n");
}
// Find the specified contact 
void SearchContact(struct contact* pc)
{
    
	char name[NAME_MAX];
	printf(" Please enter the name of the contact you are looking for :");
	scanf("%s", name);
	int ret = FindByName(pc, name);
	if (ret == -1)
	{
    
		printf(" Check no one ！\n");
		return;
	}
	printf("%-5s\t%-5s\t%-5s\t%-15s\t\t%-20s\n", " full name ", " Age ", " Gender ", " Telephone ", " Address ");// Print a title 

	printf("%-5s\t%-5d\t%-5s\t%-15s\t\t%-20s\n", pc->data[ret].name,
		pc->data[ret].age, pc->data[ret].sex, pc->data[ret].tel, pc->data[ret].addr);
}
// Modify contact information 
void ModifyContact(struct contact* pc)
{
    
	char name[NAME_MAX];
	printf(" Please enter the contact name to be modified ：");
	scanf("%s", name);
	int ret = FindByName(pc, name);
	if (ret == -1)
	{
    
		printf(" Check no one \n");
		return;
	}
	struct PeopInfo tmp = {
     0 };
	printf(" Please enter a new name ：");
	scanf("%s", tmp.name);
	printf(" Please enter a new age ：");
	scanf("%d", &(tmp.age));
	printf(" Please enter a new gender ：");
	scanf("%s", tmp.sex);
	printf(" Please enter a new phone number ：");
	scanf("%s", tmp.tel);
	printf(" Please enter a new address :");
	scanf("%s", tmp.addr);

	pc->data[ret] = tmp;

	printf(" Successfully modified the specified contact information ！\n");
}
// Destroy the address book 
void DestoryContact(struct contact* pc)
{
    
	free(pc->data);
	pc->data = NULL;
	pc->sz = 0;
	pc->capacity = 0;
}
// Sort by age 
int compare(const void* e1, const void* e2)
{
    
	return ((struct PeopInfo*)e1)->age-((struct PeopInfo*)e2)->age;
}
void SortContact(struct contact* pc)
{
    
	if (pc->sz == 0)
	{
    
		printf(" The address book is currently empty ！\n");
		return;
	}
	qsort(pc->data, pc->sz, sizeof(struct PeopInfo), compare);
	printf(" Rank success by age ！\n");
}
// Save address book information 
void SaveContact(struct contact* pc)
{
    
	FILE* pf = fopen("contact.txt", "wb");// Binary write 
	if (pf == NULL)
	{
    
		perror("SaveContact::fopen");
		return;
	}
	// File opened successfully 
	for (int i = 0; i < pc->sz; i++)
	{
    
		fwrite(&(pc->data[i]), sizeof(struct PeopInfo), 1, pf); 
	}
	fclose(pf);
	pf = NULL;
}

---

//test.c
#include "contact.h"
void menu()
{
    
	printf("***********************************\n");
	printf("******** 1.add 2.del *******\n");
	printf("******** 3.search 4.modify *******\n");
	printf("******** 5.show 6.sort *******\n");
	printf("******** 0.exit *******\n");
	printf("***********************************\n");
}
enum Option
{
    
	EXIT,
	ADD,
	DEL,
	SEARCH,
	MODIFY,
	SHOW,
	SORT
};
int main()
{
    
	int input = 0;
	struct contact con;// Create an address book 
	// Initialize address book 
	initContact(&con);
	do
	{
    
		menu();
		printf(" Please enter your choice :>");
		scanf("%d", &input);
		switch (input)
		{
    
		case ADD:
			AddContact(&con);
			break;
		case DEL:
			DelContact(&con);
			break;
		case SEARCH:
			SearchContact(&con);
			break;
		case MODIFY:
			ModifyContact(&con);
			break;
		case SHOW:
			ShowContact(&con);
			break;
		case EXIT:
			// sign out cmd At the window , You need to save the address book information to the file first 
			SaveContact(&con);
			DestoryContact(&con);
			printf(" Exit address book successfully ！\n");
			break;
		case SORT:
			SortContact(&con);
			break;
		default:
			printf(" Incorrect input , Please reselect ：");
			break;
		}
	} while (input);
	return 0;
}

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