Implementation of address book (file version)

Design requirements

Everyone's information doesn't just have numbers , We can also design gender and age , So the subject we choose is a structure

struct info
{
    
	char name[MAX_NAME];
	char sex[MAX_SEX];
	char phone[MAX_PHONENUMBER];
	char address[MAX_ADDRESS];
	int age;
};

The dynamic version is better when designing the address book , So we add a structure to the original structure

struct contact
{
    
	struct info* data;
	int sz;
	int capacity;
};

among capacity Indicates the capacity size ,sz Indicates the current number of contacts in the address book , When capacity==sz Capacity expansion is required at this time

Test.c

First, we need to write an enumeration constant

enum choice
{
    
	EXIT,// sign out 
	ADD,// Add a Contact 
	DEL,// Delete Contact 
	SEARCH,// Find contacts 
	MODIFY,// Modify address book 
	SHOW,// Show the address book 
	CLEAR,// Clear address book 
	SORT// Sort the address book 
};

If there is no assignment, it defaults from 0 Start , In this way, even if others only see our document, they can immediately understand the meaning of the numerical options .
Then there are some routine operations similar to the previous ones

void menu()
{
    
	printf("****************************************************************************\n");
	printf("***********************0. Exit address book *******1. Add a Contact ***********************\n");
	printf("***********************2. Delete Contact *******3. Find contacts ***********************\n");
	printf("***********************4. Modify contact ********5. Show the address book **********************\n");
	printf("***********************6. Format address book ******7, Sort contacts *******************\n");
	printf("******************************************************************************\n");

}
int main()
{
    
	struct contact con;
	// Initialize address book 
	Init_Contact(&con);
	int input = 0;
	int size = 0;// Record how many people there are currently 
	do
	{
    
		menu();
		printf(" Please select ->\n");
		scanf("%d", &input);
		switch (input)
		{
    
		case ADD:
			Add_Contact(&con);
			break;
		case DEL:
			Del_Contact(&con);
			break;
		case SEARCH:
			Search_Contact(&con);
			break;
		case MODIFY:
			Modify_Contact(&con);
			break;
		case SHOW:
			system("cls");
			Show_Contact(&con);
			break;
				case CLEAR:
					Clear_Contact(&con);
					break;
				case SORT:
					Sort_Contact(&con);
				default :
					printf(" Wrong selection. Please re select ->\n");

		}
	} while (input);
    
	return 0;
}

contact.h

 #define _CRT_SECURE_NO_WARNINGS 1
#pragma once
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<assert.h>
#include<Windows.h>
#define MAX_NAME 20
#define MAX_AGE 20
#define MAX_PHONENUMBER 20
#define MAX_ADDRESS 20
#define MAX_SEX 10
#define DEFAULT_SZ 3
struct info
{
    
	char name[MAX_NAME];
	char sex[MAX_SEX];
	char phone[MAX_PHONENUMBER];
	char address[MAX_ADDRESS];
	int age;
};
struct contact
{
    
	struct info* data;
	int sz;
	int capacity;
};
// Initialize address book 
void Init_Contact(struct contact* pf);
// Determine whether the address book needs to be expanded 
void Check_Capacity(struct contact* pf);
// Add a Contact 
void Add_Contact(struct contact* pf);
void Show_Contact(struct contact* pf);// Print address book 
void Del_Contact(struct contact* pf);// Delete Contact 
void Search_Contact(struct contact* pf);// Find contacts 
void Modify_Contact(struct contact* pf);// Modify contact 
void Clear_Contact(struct contact* pf);// Format address book 
void Sort_Contact(struct contact* pf);// Sort contacts in the address book 
void Save_Contact(struct contact* pf);// Save the contents of the address book to a file 

contact.c

Focus on two functions

1, Save the contents of the address book to a file

Storage uses binary storage ：
Because the difference between a text file and a binary file is just the difference in encoding , So their advantages and disadvantages are the advantages and disadvantages of coding , Look for a coded book and it will be clear . It is generally believed , Text file encoding is based on character length , It's easier to decode ; Binary encoding is variable length , So it's flexible , Storage utilization is higher , It's harder to decode （ Different binary file formats , There are different ways of decoding ）. About space utilization , think about it , Binary files can even use a bit to represent a meaning ( Bit operation ), And any meaning of the text file is at least one character
That is, there is no conversion time in the storage （ Don't encode or decode , Write the value directly ）, So we use binary storage . Other words only need to understand fwrite and fread That's all right.

void Save_Contact(struct contact* pf)// Save the contents of the address book to a file 
{
    
	assert(pf);
	FILE* ps = fopen("contact.txt", "wb");
	if (ps == NULL)
	{
    
		printf(" File opening failure \n");
		return;
	}
	int i = 0;
	for (i = 0; i < pf->sz; i++)
	{
    
		fwrite(&(pf->data[i]), sizeof(struct info), 1, ps);// Write the structure data to the file 
	}
	printf(" Address book saved successfully !\n");
	fclose(ps);
	ps = NULL;




}

2, Initialize address book

When initializing the address book, you should import the contents of the address book in the file into the structure , Because it doesn't rule out checking the address book at the beginning .

void Init_Contact(struct contact* pf)// To initialize the address book, you also need to import the contents of the file into the structure 
{
    
	pf->data = (struct info*)malloc(sizeof(struct info) * 3);
	if (pf->data == NULL)
	{
    
		printf(" Address book initialization error \n");
		return 0;

	}
	pf->sz = 0;
	pf->capacity = DEFAULT_SZ;
	FILE* ps = fopen("contact.txt", "rb");
	if (ps == NULL)
	{
    
		printf(" File opening failure \n");
		return;
	}
	while (fread(&(pf->data[pf->sz]), sizeof(struct info), 1, ps))
	{
    
		Check_Capacity(pf);
		pf->sz++;
	}


}

complete contact.c Code

#define _CRT_SECURE_NO_WARNINGS 1
#include"contact.h"
void Init_Contact(struct contact* pf)// To initialize the address book, you also need to import the contents of the file into the structure 
{
    
	pf->data = (struct info*)malloc(sizeof(struct info) * 3);
	if (pf->data == NULL)
	{
    
		printf(" Address book initialization error \n");
		return 0;

	}
	pf->sz = 0;
	pf->capacity = DEFAULT_SZ;
	FILE* ps = fopen("contact.txt", "rb");
	if (ps == NULL)
	{
    
		printf(" File opening failure \n");
		return;
	}
	while (fread(&(pf->data[pf->sz]), sizeof(struct info), 1, ps))
	{
    
		Check_Capacity(pf);
		pf->sz++;
	}


}
void Check_Capacity(struct contact* pf)
{
    
	assert(pf);
	if (pf->capacity == pf->sz)
	{
    
		// Need to increase capacity 
		struct inof*cur = (struct info*)realloc(pf->data, (pf->capacity + 2) * sizeof(struct info));
		if (cur != NULL)
		{
    
			pf->data = cur;
			pf->capacity += 2;
			printf(" Successful expansion \n");

		}
		else
		{
    
			printf(" Capacity increase failed \n");
		}
	}
}

void Add_Contact(struct contact* pf)
{
    
	// As long as you add contact information, you have to check whether you need to expand 
	Check_Capacity(pf);
	printf(" Please enter a name :\n");
	scanf("%s", &(pf->data[pf->sz].name));
	printf(" Please enter gender :\n");
	scanf("%s", &(pf->data[pf->sz].sex));
	printf(" Please enter age :\n");
	scanf("%d", &(pf->data[pf->sz].age));

	printf(" Please enter the address :\n");
	scanf("%s", &(pf->data[pf->sz].address));

	printf(" Please enter : number \n");
	scanf("%s", &(pf->data[pf->sz].phone));
	pf->sz++;
	printf(" Add contact succeeded !\n");

	

}
void Show_Contact(struct contact* pf)// Print address book 
{
    
	if (pf->sz == 0)
	{
    
		printf(" Address book is empty ！\n");

	}
	else
	{
    
		printf("%-20s\t%-5s\t%-4s\t%-30s\t%-13s\t\n", " full name ", " Gender ", " Age ", " Address ", " number ");
		int i = 0;
		while (i < pf->sz)
		{
    
			// data 
			printf("%-20s\t%-5s\t%-4d\t%-30s\t%-13s\t\n", pf->data[i].name, pf->data[i].sex,
				pf->data[i].age, pf->data[i].address, pf->data[i].phone);
			i++;
		}
	}
}
// Find contacts by name 
int find_by_name(struct contact* pf, char* name)
{
    
	int i = 0;
	while (i < pf->sz)
	{
    
		if (strcmp(pf->data[i].name, name) == 0)
			return i;
	}
	return -1;
}
void Del_Contact(struct contact* pf)// Delete Contact 
{
    
	if (pf->sz == 0)
	{
    
		printf(" Address book is empty , Cannot delete ！\n");
	}
	else
	{
    
		char name[MAX_NAME];
		printf(" Please enter the name of the contact to be deleted \n");
		scanf("%s", name);
		int pos = find_by_name(pf,name);
		if (pos == -1)
		{
    
			printf(" The contact does not exist , Please re-enter \n");

		}
		else
		{
    
			for (int j = pos; j < pf->sz - 1; j++)
				pf->data[j] = pf->data[j + 1];
			pf->sz--;
			printf(" Delete contact successfully ！\n");
		}
	}
}
void Search_Contact(struct contact* pf)
{
    
	if (pf->sz == 0)
	{
    
		printf(" Address book is empty , Can't find ！\n");
	}
	else
	{
    
		char name[MAX_NAME];
		printf(" Please enter the name of the contact to be deleted \n");
		scanf("%s", name);
		int pos = find_by_name(pf, name);
		if (pos == -1)
		{
    
			printf(" The contact does not exist , Please find again \n");

		}
		else
			
		{
    
			printf("%-20s\t%-5s\t%-4s\t%-30s\t%-13s\t\n", " full name ", " Gender ", " Age ", " Address ", " number ");
			printf("%-20s\t%-5s\t%-4d\t%-30s\t%-13s\t\n", pf->data[pos].name, pf->data[pos].sex,
				pf->data[pos].age, pf->data[pos].address, pf->data[pos].phone);
		}

	}
}
void Modify_Contact(struct contact* pf)// Modify contact 
{
    
	char name[MAX_NAME];
	printf(" Please enter the name of the contact to be modified :");
	scanf("%s", name);
	int pos = find_by_name(pf,name);
	if (pos == -1)
	{
    
		printf(" The contact does not exist , Please re-enter \n");
		return;
	}
	else
	{
    
		printf(" Please enter a name :");
		scanf("%s", pf->data[pos].name);
		printf(" Please enter gender :");
		scanf("%s", pf->data[pos].sex);
		printf(" Please enter age :");
		scanf("%d", &pf->data[pos].age);
		printf(" Please enter the address :");
		scanf("%s", pf->data[pos].address);
		printf(" Please enter the number :");
		scanf("%s", pf->data[pos].phone);
		printf(" Contact modified successfully ！\n");
	}





}
void Clear_Contact(struct contact* pf)// Format address book 
{
    
	memset(pf->data, 0, sizeof(pf->data));
	pf->sz = 0;
	printf(" Format successful !\n");



}
int Compare_by_name(const void* e1, const void* e2)
{
    
	return strcmp(((struct info*)e1)->name, ((struct info*)e2)->name);
}
int Compare_by_age(const void* e1, const void* e2)
{
    
	return ((struct info*)e1)->age - ((struct info*)e2)->age;
}
int Compare_by_address(const void* e1, const void* e2)
{
    
	return strcmp(((struct info*)e1)->address, ((struct info*)e2)->address);

}
void Sort_Contact(struct contact* pf)// Sort contacts in the address book 
{
    
	printf(" Please select sort by 1: full name 2: Age 3: Home address \n");
	int input = 0;
	scanf("%d", &input);
	switch (input)
	{
    
	case 1:
		qsort(pf->data, pf->sz, sizeof(pf->data[0]), Compare_by_name);
		printf(" Sort success ！\n");
		break;
	case 2:
		qsort(pf->data, pf->sz, sizeof(pf->data[0]), Compare_by_age);
		printf(" Sort success ！\n");
		break;
	case 3:
		qsort(pf->data, pf->sz, sizeof(pf->data[0]), Compare_by_address);
		printf(" Sort success ！\n");
		break;









	}





}
void Save_Contact(struct contact* pf)// Save the contents of the address book to a file 
{
    
	assert(pf);
	FILE* ps = fopen("contact.txt", "wb");
	if (ps == NULL)
	{
    
		printf(" File opening failure \n");
		return;
	}
	int i = 0;
	for (i = 0; i < pf->sz; i++)
	{
    
		fwrite(&(pf->data[i]), sizeof(struct info), 1, ps);// Write the structure data to the file 
	}
	printf(" Address book saved successfully !\n");
	fclose(ps);
	ps = NULL;




}

In fact, most of the code of the address book is not very difficult , But the storage of files can be appropriately referred to hh