C language takes you to tear up the address book

To achieve an address book , First , We need to know What we want to achieve is what functions the address book has ,

First Think about this address book What is it , The key is —— Store and display contacts ; Store and display its name ; Age ; Gender ; Address ; also   Phone number ; No phone number ; How to practice others ; How can I call an address book ？

In addition to storing and displaying contacts We need to have at least Add, delete, search and change ; Finally, we hope to have one Sort The function of .

I know so much , We have A general direction

First

Have a simple initial interface like this ：

#include<stdio.h>
void Add()
{}
void Del()
{}
void Search()
{}
void Show()
{}
void Modify()
{}
void Sort()
{}

void menu()
{
	printf("***1.(Add)   ***\n");
	printf("***2.(Del)   ***\n");
	printf("***3.(Search)***\n");
	printf("***4.(Modify)***\n");
	printf("***5.(Show)  ***\n");
	printf("***6.(Sort)  ***\n");
	printf("***0.(Exit)  ***\n");
}

int main()
{
	int input = 0;
	do
	{
        menu();   // Give me a menu   Prompt the function performed 
        printf(" Please enter the function to be performed ： ");
	    scanf("%d", &input);
		switch(input)
		{
		case 1:Add();
				break;
		case 2:Del();
				break;
		case 3:Search();
				break;
		case 4:Modify();
				break;
		case 5:Show();
				break;
		case 6:Sort();
				break;
		case 0: printf(" Exit address book \n");
				break;
		default:printf(" Input error \n");
				break;
		}
	} while (input);
}

Here are the results of the run ：

So we have completed the first step ;

The second step Is to create variables ;

It is convenient for us to create variables with structures ：

struct People
{
	char name[10];
	int age;       // age Is the integer variable 
	char sex[10];
	char tele[11];
	char address[10];
};
struct Contact
{
	people date[100];  // Initially we store 100 Personal information   So we give people type 
	int count;        //  Record the number of people in the current address book 
};
//——————————————————————————
typedef struct People
{
	char name[10];
	int age[10];
	char sex[10];
	char tele[11];
	char address[10];
}People;
typedef struct Contact
{
	int date[100];
	int count;
}Contact;

For the convenience of later reference to the structure We make use of typedef To name the structural weight .

The above is the basic framework of this address book Now? We construct the function step by step to realize our function .

Mention functions ; Let's not worry about writing those function functions directly

Think about it our Contact Is it not initialized yet ;

So let's build one Contact Variable

Contact con;    //  Construct a Contact Variable 
initContact(&con);  //  initialization 

Then start writing initialization functions

void initContact(Contact*pc) //  initialization  pc  The type is Contact*
{
	assert(pc);  // prevent pc Null pointer 
	pc->count = 0;
	memset(pc->date, 0, sizeof(pc->date));
	//memset  Copy characters  0)( An unsigned character ） To ginseng 
    // Count  pc->date The front of the string to which it refers  sizeof(pc->date) Characters .
}

Initialization finished , Let's write Add function

case 1:Add(&con);
	break;

Pay special attention when printing here   A little carelessness is wrong （ Painful lesson ）

// name It's an array name Itself is the address
// age Is an integer variable   Need to get the address

void Add(Contact* pc)
{
	assert(pc);
	//  First of all   Yes pc  Judge   Whether it is a null pointer    Null pointers cannot be dereferenced 
	//  Judge  count  Have you exceeded date The range that can be stored 
	if (pc->count == 100)
	{
		printf(" The number is full , Please try again after processing ");
		return;
	}
	printf(" Please enter a name ：");
	scanf("%s", pc->date[pc->count].name);  // name It's an array name   Itself is the address 
	printf(" Please enter age ：");
	scanf("%d", &(pc->date[pc->count].age)); // age  Is an integer variable    Need to get the address 
	printf(" Please enter gender ：");
	scanf("%s", &pc->date[pc->count].sex);
	printf(" Please input the phone number ：");
	scanf("%s", pc->date[pc->count].tele);
	printf(" Please enter the address ：");
	scanf("%s", pc->date[pc->count].address);
	pc->count = pc->count + 1;    // count  Record the number of people stored   Remember to add 1 
	printf(" Increase success \n");
}

Here is Del function

case 2:Del(&con);
	break;

int find_name(Contact* pc,char name1[])
{
	assert(pc);
	int i = 0; // for  Loop through to find 
	for (i = 0; i < pc->count; i++)
	{
		if (0 == strcmp(name1, pc->date[i].name))
			return i;  // return  i  Convenient deletion 
	}
	return -1;
}

void Del(Contact* pc)
{
	assert(pc);
	// First of all, judge   Whether the address book is empty 
	if(pc->count == 0)
	{
		printf(" Address book is empty , Not delete \n");
	}
	printf(" Please enter the name of the contact to be deleted ：");
	char name1[20] = { 0 };
	scanf("%s", &name1);
	//  Know before deleting   We know the location of this contact 
	//  You cannot apply for deletion directly 
	//  So we have to find   The location of this contact   And determine whether there is 
	//  We assume that   No one in this contact has the same name  
	//  Let's follow   Name to find 
	int ret = find_name(pc, name1);  //  Give me one  ret  To accept the return value 
	// Use overwrite to delete 
	if (ret == 0)
	{
		printf(" No such contact , Please check and try again \n");
		return 0;
	}
	else if (ret != -1)
	{
		int i = 0;
		for (i = ret; i < pc->count - 1; i++)
		{
			pc->date[ret] = pc->date[ret + 1];
		}
	}
	pc->count = pc->count - 1;
	printf(" Delete successful \n");
}

The next step is Search function

case 3:Search(&con);
		break;

Before the same search We know the location of this contact    

We need to find The location of this contact And determine whether there is

  We assume that No one in this contact has the same name    Let's follow Name to find

Still use find_name This function

void Search(Contact* pc)
{
	assert(pc);
	printf(" Please enter the name of the person you want to find :");
	// Old rules   We must first determine whether the contact we are looking for exists 
	char name1[20] = { 0 };
	scanf("%s", &name1);
	int ret = find_name(pc, name1);  //  Give me one  ret  To accept the return value 
	if (ret == -1)
	{
		printf(" No such contact , Please check and try again \n");
		return ;
	}
		// According to the width of each character , Align left to output them .
	printf("%-20s\t%-10s\t%-10s\t%-11s\t%-10s\n", " name ", " Age ", " Gender ", " Telephone ", " Address ");
	printf("%-20s\t%-10d\t%-10s\t%-11s\t%-10s\n",
		pc->date[ret].name,
		pc->date[ret].age,
		pc->date[ret].sex,
		pc->date[ret].tele,
		pc->date[ret].address);
	
}

And then it's Modify function

case 4:Modify(&con);
	break;

Before the same modification We know the location of this contact    

We need to find The location of this contact And determine whether there is

  We still assume No one in this contact has the same name    Let's follow Name to find

Still use find_name This function

void Modify(Contact* pc)
{
	assert(pc);
	printf(" Please enter the name of the person to modify :");
	// Old rules   We must first judge whether the modified contact exists 
	char name1[20] = { 0 };
	scanf("%s", &name1);
	int ret = find_name(pc, name1);  //  Give me one  ret  To accept the return value 
	if (ret == -1)
	{
		printf(" No such contact , Please check and try again \n");
		return;
	}
	printf(" Please enter a name ：");
	scanf("%s", pc->date[ret].name);
	printf(" Please enter age ：");
	scanf("%d", pc->date[ret].age);
	printf(" Please enter gender ：");
	scanf("%s", &pc->date[ret].sex);
	printf(" Please input the phone number ：");
	scanf("%s", pc->date[ret].tele);
	printf(" Please enter the address ：");
	scanf("%s", pc->date[ret].address);
	printf(" Modification successful \n");
}

Here is Show function

case 5:Show(&con);
	break;

void Show(Contact* pc)
{
	assert(pc);
	int i = 0; // for  Loop through print 
	printf("%-20s\t%-10s\t%-10s\t%-11s\t%-10s\n", " name ", " Age ", " Gender ", " Telephone ", " Address ");
	for (i = 0; i < pc->count; i++)
	{
		printf("%-20s\t%-10d\t%-10s\t%-11s\t%-10s\n",
			pc->date[i].name,
			pc->date[i].age,
			pc->date[i].sex,
			pc->date[i].tele,
			pc->date[i].address);
	}

}

the last one function  

case 6:Sort(&con);
				break;

Want to use qsort function I don't know the usage   here

int com_by_name(const void* e1,const void*e2)
{
	strcmp(((People*)e1)->name, ((People*)e2)->name);
}

void Sort(Contact* pc)
{
	assert(pc);
	//  We still sort by name 
	qsort(pc->date,pc->count, sizeof(People),com_by_name);
	printf(" Sort success \n");
}

———————————————————————————————————————————

Manual split line

Above we will take the simple version of the address book It's done

The complete code is attached below

#define _CRT_SECURE_NO_WARNINGS

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<assert.h>
typedef struct People
{
	char name[10];
	int age;
	char sex[10];
	char tele[11];
	char address[100];
}People;

typedef struct Contact
{
	People date[100];
	int count;         //  Record the number of people in the current address book 
}Contact;

void initContact(Contact*pc) //  initialization  pc  The type is Contact*
{
	assert(pc);  // prevent pc Null pointer 
	pc->count = 0;
	memset(pc->date, 0, sizeof(pc->date));
	//memset  Copy characters  0)( An unsigned character ） To parameter  pc->date The front of the string to which it refers  sizeof(pc->date) Characters .
}



void Add(Contact* pc)
{
	assert(pc);
	//  First of all   Yes pc  Judge 
	//  Judge  count  Have you exceeded date The range that can be stored 
	if (pc->count == 100)
	{
		printf(" The number is full , Please try again after processing \n");
		return;
	}
	printf(" Please enter a name ：");
	scanf("%s", pc->date[pc->count].name);  // name It's an array name   Itself is the address 
	printf(" Please enter age ：");
	scanf("%d", &(pc->date[pc->count].age)); // age  Is an integer variable    Need to get the address 
	printf(" Please enter gender ：");
	scanf("%s", pc->date[pc->count].sex);
	printf(" Please input the phone number ：");
	scanf("%s", pc->date[pc->count].tele);
	printf(" Please enter the address ：");
	scanf("%s", pc->date[pc->count].address);
	pc->count = pc->count + 1;
	printf(" Increase success \n");
	return;
}
int find_name(Contact* pc,char name1[])
{
	assert(pc);
	int i = 0; // for  Loop through to find 
	for (i = 0; i < pc->count; i++)
	{
		if (0 == strcmp(name1, pc->date[i].name))
			return i;  // return  i  Convenient deletion 
	}
	return -1;
}
void Del(Contact* pc)
{
	assert(pc);
	// First of all, judge   Whether the address book is empty 
	if(pc->count == 0)
	{
		printf(" Address book is empty , Not delete \n");
	}
	printf(" Please enter the name of the contact to be deleted ：");
	char name1[20] = { 0 };
	scanf("%s", &name1);
	//  Know before deleting   We know the location of this contact 
	//  You cannot apply for deletion directly 
	//  So we have to find   The location of this contact   And determine whether there is 
	//  We assume that   No one in this contact has the same name  
	//  Let's follow   Name to find 
	int ret = find_name(pc, name1);  //  Give me one  ret  To accept the return value 
	// Use overwrite to delete 
	if (ret == -1)
	{
		printf(" No such contact , Please check and try again \n");
		return ;
	}
	else if (ret != -1)
	{
		int i = 0;
		for (i = ret; i < pc->count - 1; i++)
		{
			pc->date[ret] = pc->date[ret + 1];
		}
	}
	pc->count = pc->count - 1;
	printf(" Delete successful \n");
}
void Search(Contact* pc)
{
	assert(pc);
	printf(" Please enter the name of the person you want to find :");
	// Old rules   We must first determine whether the contact we are looking for exists 
	char name1[20] = { 0 };
	scanf("%s", name1);
	int ret = find_name(pc, name1);  //  Give me one  ret  To accept the return value 
	if (ret == -1)
	{
		printf(" No such contact , Please check and try again \n");
		return ;
	}
		// According to the width of each character , Align left to output them .
	printf("%-20s\t%-3s\t%-10s\t%-11s\t%-10s\n", " name ", " Age ", " Gender ", " Telephone ", " Address ");
	printf("%-20s\t%-3d\t%-10s\t%-11s\t%-10s\n",
		pc->date[ret].name,
		pc->date[ret].age,
		pc->date[ret].sex,
		pc->date[ret].tele,
		pc->date[ret].address);
	
}
void Show(Contact* pc)
{
	assert(pc);
	int i = 0; // for  Loop through print 
	printf("%-20s\t%-3s\t%-10s\t%-11s\t%-10s\n", " name ", " Age ", " Gender ", " Telephone ", " Address ");
	for (i = 0; i < pc->count; i++)
	{
		printf("%-20s\t%-3d\t%-10s\t%-11s\t%-10s\n",
			pc->date[i].name,
			pc->date[i].age,
			pc->date[i].sex,
			pc->date[i].tele,
			pc->date[i].address);
	}

}
void Modify(Contact* pc)
{
	assert(pc);
	printf(" Please enter the name of the person to modify :");
	// Old rules   We must first judge whether the modified contact exists 
	char name1[20] = { 0 };
	scanf("%s", &name1);
	int ret = find_name(pc, name1);  //  Give me one  ret  To accept the return value 
	if (ret == -1)
	{
		printf(" No such contact , Please check and try again \n");
		return;
	}
	printf(" Please enter a name ：");
	scanf("%s", pc->date[ret].name);
	printf(" Please enter age ：");
	scanf("%d", &(pc->date[ret].age));
	printf(" Please enter gender ：");
	scanf("%s", pc->date[ret].sex);
	printf(" Please input the phone number ：");
	scanf("%s", pc->date[ret].tele);
	printf(" Please enter the address ：");
	scanf("%s", pc->date[ret].address);
	printf(" Modification successful \n");
}
int com_by_name(const void* e1,const void*e2)
{
	strcmp(((People*)e1)->name, ((People*)e2)->name);
}

void Sort(Contact* pc)
{
	assert(pc);
	//  We still sort by name 
	qsort(pc->date,pc->count, sizeof(People),com_by_name);
	printf(" Sort success \n");
}

void menu()
{
	printf("***1.(Add)   ***\n");
	printf("***2.(Del)   ***\n");
	printf("***3.(Search)***\n");
	printf("***4.(Modify)***\n");
	printf("***5.(Show)  ***\n");
	printf("***6.(Sort)  ***\n");
	printf("***0.(Exit)  ***\n");
}


int main()
{
	int input = 0;
	Contact con;    //  Construct a Contact Variable 
	initContact(&con);  //  initialization 
	do
	{
		menu();   // Give me a menu   Prompt the function performed 
		printf(" Please enter the function to be performed ： ");
		scanf("%d", &input);
		switch(input)
		{
		case 1:Add(&con);
				break;
		case 2:Del(&con);
				break;
		case 3:Search(&con);
				break;
		case 4:Modify(&con);
				break;
		case 5:Show(&con);
				break;
		case 6:Sort(&con);
				break;
		case 0: printf(" Exit address book \n");
				break;
		default:printf(" Input error \n");
				break;
		}
	} while (input);

}