About student management system (registration, login, student side)

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Preface

Here is the implementation of some small modules of the student management system ：

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Tips ： The following is the main body of this article , The following cases can be used for reference

One 、 Registration module

How to write the registration module ？
1. First, you need to create a file to save the registered account and password , This eliminates the need to re register every time you log in , Just check whether this account exists in the file when logging in

2. Then we need to judge whether the account number entered each time is legal .（ It refers to whether the entered student ID really exists ） At this time, we also need a file , To store all the student information that can be used to register .

So we need to judge whether the account number entered by the user corresponds Real students , And this account Not registered , You also need to check Save the account and password .

1. Registration module

void zhuce() {
    // Here is the registration module 
	Sleep(1000);
	system("cls");
	// Registered account 
	printf(" Please enter your account number :");
	char num[NUM_S];
	scanf("%s", num);
	Node* head = (Node*)malloc(sizeof(Node));
	head = duqu_class1();// Here is to find out whether the account is legal 
	int k = -1;
	while (head) {
    
		if (strcmp(head->num, num) == 0) {
    
			k = 0;
			break;
		} else {
    
			k = 1;
			head = head->next;
		}
	}
	if (k == 1) {
    
		printf(" I can't find your account , Please re-enter !\n");
		zhuce();
	}
	struct count* count = (struct count*)malloc(sizeof(count));
	count = duqu_count();// Judge whether the entered account has been registered 
	while (count) {
    
		if (strcmp(count->num, num) == 0) {
    
			printf(" This account has been registered , Please re-enter ：\n");
			zhuce();
			break;
		} else {
    
			k = 2;
			count = count->next;
		}
	}
	char password1[PASS_S];// When the account is legal and not registered, you will come to this step 
	char password2[PASS_S];// We need to ask the user to enter the password twice , Achieve the purpose of determining the password 
	if (k == 2) {
    
		printf(" Please input a password ：");
		scanf("%s", password1);
		printf(" Please confirm the password ：");
		scanf("%s", password2);
		if (strcmp(password1, password2) == 0) {
    
		// There is no direct comparison here password1 and password2, Because they are all string types , The variable name should be a string address 
			printf(" Registered successfully ！\n");
			struct count* Head = (struct count*)malloc(sizeof(struct count));
			struct count* p = Head;
			strcpy(Head->num, num);
			strcpy(Head->password, password1);
			// It should be noted that you can't directly let Head->password=password
			//password Is a string , You should use strcpy Function to copy it , The reason and the above strcmp The same function 
			save_count(Head);// For accounts that have been successfully registered , It should be saved in the account file 
			Head->next = NULL;
			Head = Head->next;

		}
	} else {
    // When the passwords entered twice are inconsistent , The user will be prompted that the passwords entered are inconsistent , Then return to the registration page 
		printf(" The two passwords are not the same ！ Please re-enter ：\n");
		zhuce();
	}
}

2. Judge whether the account exists

Read the information in the file （ There needs to be a named class1.txt The file of ）, Read this file

Node* duqu_class1() {
    // Read the information in the file into the linked list 
	Sleep(1000);
	system("cls");
	FILE* fp;
	fp = fopen("class1.txt", "r");
	Node* head, * p, * end;
	head = p = (Node*)malloc(sizeof(Node));
	while (!feof(fp)) {
    
		end = (Node*)malloc(sizeof(Node));
		fscanf(fp, "%s %s %s %d %d %d\n", end->name, end->num, end->class, &end->score1, &end->score2, &end->score3);
		p->next = end;
		p = end;
	}
	fclose(fp);
	head = head->next;
	p->next = NULL;
	return head;
}

3. Judge whether the account is not registered

Here is the function to judge whether the read account has been registered , Note the return type of the function here （count.txt） It is a file used to store all registered accounts and passwords

struct count* duqu_count() {
    
	Sleep(1000);
	system("cls");
	FILE* fp = fopen("count.txt", "r");
	if (fp == NULL) {
    
		perror(fopen);
		return;
	}
	struct count* Head, * p, * end;
	Head = p = (struct count*)malloc(sizeof(struct count));
	while (!feof(fp)) {
    
		end = (struct count*)malloc(sizeof(struct count));
		fscanf(fp, "%s %s\n", end->num, end->password);
		p->next = end;
		p = end;
	}
	fclose(fp);
	Head = Head->next;
	p->next = NULL;
	return Head;
}

4. Save the successfully registered account

Here is the function to save the successfully registered account and password , We still save the successfully registered account and password to count.txt In file

void save_count(struct count* head) {
    // Save the registered account 
	Sleep(1000);
	system("cls");
	struct count* con = (struct count*)malloc(sizeof(struct count));
	FILE* fp;
	fp = fopen("count.txt", "a");
	if (fp == NULL) {
    
		perror(fopen);
	} else {
    
		con = head;
		struct count* Headcount = con;
		fprintf(fp, "%s %s\n", con->num, con->password);
		con = con->next;
		printf(" The account and password have been saved successfully !\n");
		fclose(fp);
	}
}

Two 、 Login module

1. Sign in

When the user enters , We only need Read the previous file storing the account and password , Just check whether the account number and password entered by the user are correct .

void denglu_stu() {
    // Log in to the student account 
	Sleep(1000);
	system("cls");
	char num[NUM_S];
	printf(" Please enter your account number ：");
	scanf("%s", num);
	char password[PASS_S];
	printf(" Please input a password ：");
	scanf("%s", password);
	int i = 0;
	struct count* Head = duqu_count();
	// This function has been previously declared , Don't explain too much 
	while (Head) {
    
		if (strcmp(Head->num, num) == 0 && strcmp(Head->password, password) == 0) {
    
			printf(" Login successful !\n");
			menu_stu();
			i = 1;
			break;
		} else {
    
			Head = Head->next;
		}
	}
	if (i != 1) {
    
		printf(" The student number or password entered is incorrect , Or this student ID has not been registered !\n");
	}
}

3、 ... and . Students check their scores

struct student* Head=NULL;
Head = duqu_class1();
// It is still the previous function of reading student information 
char num[NUM_S];
printf(" Please enter your student number ：\n");
scanf("%s", num);
int i = 0;
while (Head) {
    
	if (strcmp(Head->num, num) == 0) {
    
		printf("%d %d %d", Head->score1, Head->score2, Head->score3);
		i = 1;
		break;
	} else {
    
		Head = Head->next;
	}
}
if (i != 1) {
    
	printf(" The student number entered is incorrect , Please re-enter !\n");
	chaxun(k);
}

Four . Students check their grades

struct student* Head=NULL;
Head = duqu_class1();
while (Head) {
    
		printf("%5s %5s %5s %5d %5d %5d\n", Head->name, Head->num, Head->class, Head->score1, Head->score2, Head->score3);
		Head = Head->next;
	}

summary

Register in the student management system , Login and other modules , Note that we need to operate the file . Be sure to pay attention to the way the file is opened , Otherwise, you may find that you have got another empty file after the operation .