我的银行记录管理程序中的 fread 和 fwrite 出现问题

Question

我正在做我的银行记录管理系统项目，在读取文件时遇到问题。我的文件名是“name_of_the_user.txt”并以wb+模式打开。我有一个结构，其中包含一些字段，例如名称、地址、金钱等。我一直在尝试通过将数据读入结构 BMS u1 来存款和取款，然后执行以下功能，但我认为读取此结构会导致文件损坏和一些垃圾值。请帮忙。

    #include <stdio.h>
#include <conio.h>
#include <stdlib.h>
#include <string.h>
#include <windows.h>
void main_menu(char*);
void update_acc(char *);
// void deposit( char *);
// void withdrawl( char *);

struct BMS
{
    char name[20];
    char mailid[20];
    unsigned long long contact;
    unsigned long long adhar;
    int date, year, month;
    char address[100];
    char password[15];
    int money;
};
struct balance{
    char namefrom[20];
    char nameto[20];
    long int money;
};
void gotoxy(int x, int y)
{
    COORD c;
    c.X = x;
    c.Y = y;

    SetConsoleCursorPosition(
        GetStdHandle(STD_OUTPUT_HANDLE), c);
}
void view_acc(char username[])
{
    FILE *fp;
    struct BMS u1;
    char filename[20];
    strcpy(filename, username);
    fp = fopen(strcat(filename, ".bin"), "rb");
    if(fp==NULL){
        printf("Error viewing account details.");
    }
    fread(&u1, sizeof(u1), 1, fp);
    printf("%s\n", u1.name);
    printf("%llu\n", u1.contact);
    printf("%llu\n", u1.adhar);
    
    printf("%d - %d - %d\n", u1.date, u1.month, u1.year);
    printf("%s\n", u1.address);
    printf("%s\n", u1.mailid);
    printf("Balance : %d\n", u1.money);
    fclose(fp);
}
void create_acc()
{
    system("cls");
    FILE *fp;
    struct BMS u1;
    int k=0;
    char ch1, temp, filename[20];
    scanf("%c",&temp);
    u1.money = 0;
    printf("\t\t\tFill in the details \n");
    printf("Name of account holder: ");
    scanf("%[^\n]", &u1.name);
    printf("Enter DOB : ");
    printf("Date : ");
    scanf("%d" , &u1.date);
    printf("\nMonth : ");
    scanf("%d", &u1.month);
    printf("\nYear : ");
    scanf("%d", &u1.year);
    printf("Enter your mobile number : ");
    scanf("%llu", &u1.contact);
    printf("Enter your Aadhar ID : ");
    scanf("%llu", &u1.adhar);
    scanf("%c",&temp);
    printf("Enter user email : ");
    scanf("%[^\n]", &u1.mailid);
    scanf("%c",&temp);
    printf("Enter Your Address : ");
    scanf("%[^\n]", &u1.address);
    printf("Create PIN : ");
    for(k=0; k<15; k++)
     {
             ch1 = getch();
             u1.password[k]=ch1;
      
             if(ch1!=13 && ch1!=8)     
                   printf("*");
             if(ch1 == 13)
                   break;
      }
      u1.password[k]='\0';
      printf("\nYour created PIN is : ");
      for(k=0; k<strlen(u1.password); k++){
          printf("%c", u1.password[k]);
      }
    printf("\nYour Account has beem succesfully added to our system. Please remember your created PIN to acces your account.\n\n");
    strcpy(filename, u1.name);
    fp = fopen(strcat(filename, ".bin"), "ab");
    fwrite(&u1, sizeof(u1),1, fp);
    fclose(fp);
}
void login(){
    system("cls");
    FILE *fp;
    struct BMS u1;
    char name[20], temp, password[15],ch1, filename[20];
    int i, j, k;
    scanf("%c",&temp);
    printf("Enter your name : ");
    scanf("%[^\n]", &name);
    scanf("%c",&temp);
    printf("Enter your PIN : ");
    scanf("%s", &password);
    strcpy(filename, name);
    fp = fopen(strcat(filename, ".bin"),"rb");
    if(fp==NULL){
        printf("No account found.");
    }
    fread(&u1, sizeof(u1), 1, fp);
    
    if(!strcmp(password, u1.password)){
        printf("Login succesful.");
        fclose(fp);
        main_menu(name);
    }
    else {
        printf("Login failed wrong password.");
        fclose(fp);
    }
}
void transaction(char username[])
{
    system("cls");
    FILE *fp, *fp1, *fm;
    struct BMS u1;
    struct balance b1;
    char userfrom[20], userto[20],username1, username2, temp;
    // strcpy(username1, username);
    scanf("%c", &temp);
    printf("Transfer money to : ");
    scanf("%[^\n]", &userto);
    printf("Enter the amount to be transferred : ");
    scanf("%ld", &b1.money);
    // fp1 = fopen(strcat(username1, ".txt"), )
    strcpy(userfrom, username);
    strcpy(username, userto);
    fp = fopen(strcat(username, ".bin"), "rb");
    fm = fopen("money.bin", "ab");
    while (fread(&u1, sizeof(u1), 1, fp))
    {
        if (strcmp(userto, u1.name) == 0) {
            strcpy(b1.nameto, u1.name);
            strcpy(b1.namefrom, userfrom);
        }
    }
    fwrite(&b1, sizeof(b1), 1, fm);
    fclose(fm);
    fclose(fp);

}
void viewbalance(char username[]){
    system("cls");  
    FILE *fm;
    struct balance b1;
    char ch;
    int i=1 , money=0;
    fm = fopen("money.bin", "rb");

    int k = 5, l = 10;
    int m = 30, n = 10;
    int u = 60, v = 10;

    gotoxy(30, 2);
    printf("==== BALANCE DASHBOARD ====");
    gotoxy(30, 3);
    printf("***************************");
    gotoxy(k, l);
    printf("S NO.");
    gotoxy(m, n);
    printf("TRANSACTION ID");
    gotoxy(u, v);
    printf("AMOUNT");
    while (fread(&b1, sizeof(b1), 1, fm)) {
        if (strcmp(username, b1.nameto) == 0) {
            gotoxy(k, ++l);
            printf("%d", i);
            i++;
            gotoxy(m, ++n);
            printf("%s", b1.namefrom);

            gotoxy(u, ++v);
            printf("%ld", b1.money);
            money = money + b1.money;
        }
    }
    gotoxy(80, 10);
    printf("TOTAL AMOUNT");

    gotoxy(80, 12);
    printf("%d", money);

    getch();
    fclose(fm);
}
void deposit( char username[]){
    struct BMS u1;
    FILE *fp;
    char filename[20];
    strcpy(filename, username);
    fp = fopen(strcat(filename, ".bin"), "wb+");
    fread(&u1, sizeof(u1),1, fp);
    int amount = 0;
    printf("Enter the amount to be deposited : ");
    scanf("%d", &amount);
    u1.money = u1.money + amount;
    printf("Money succesfully deposited.");
    fseek(fp, 0, SEEK_SET);
    fwrite(&u1, sizeof(u1),1, fp);
    fclose(fp);
}
void withdrawl( char username[]){
    struct BMS u1;
    FILE *fp;
    char filename[20];
    strcpy(filename, username);
    fp = fopen(strcat(filename, ".bin"), "wb+");
    if(fp==NULL){
        printf("Error");
    }
    printf("%s", u1.name);
    if(fread(&u1, sizeof(u1),1, fp)!=0){
        printf("error");
    }
    printf("%s", u1.name);
    int amount = 0;
    printf("Enter the amount to be withdrawn : ");
    scanf("%d", &amount);
    // fread(&u1, sizeof(u1), 1, fbin
    if(u1.money<amount){
        printf("Not enough money to withdraw.\n");
    }
    else{
        u1.money = u1.money - amount;
        printf("Money succesfully withdrawn.\n");
        fseek(fp, 0, SEEK_SET);
        fwrite(&u1, sizeof(u1),1, fp);
    }
    fclose(fp);
}
void main_menu(char username[]){
    system("cls");
    char username1[20];
    strcpy(username1, username);
    while(1){
        printf("\t\t\t\tWELCOME %s\n", username);
        printf("\t\t\t\t1.View account details\n");
        printf("\t\t\t\t2.Update Account\n");
        printf("\t\t\t\t3.Make a Transaction\n");
        printf("\t\t\t\t4.To view all Transaction\n");
        printf("\t\t\t\t5.Make a Deposit\n");
        printf("\t\t\t\t6.Make a Withdrawl\n");
        printf("\t\t\t\t7.LOG OUT\n");
        int ch;
        printf("Enter your choice : ");
        scanf("%d", &ch);
        if(ch==1){
            view_acc(username1);
        }
        else if(ch==2){
            update_acc(username1);
        }
        else if(ch==3){
            transaction(username1);
        }
        else if(ch==4){
            viewbalance(username1);
        }
        else if(ch==5){
        deposit(username1);
        }
        else if(ch==6){
            withdrawl(username1);
        }
    }
}
void update_acc(char username[]){
    FILE *fp1, *fp2;
    struct BMS u1;
    struct BMS u2;
    int ch, k=0;
    char temp, ch1, filename[20];
    strcpy(filename, username);
    fp1 = fopen(strcat(filename, ".bin"), "rb");
    fp2 = fopen("copy.bin", "ab");
    if(fp1==NULL){
        printf("error updating data!\n");
    }
    printf("Press 1 to update Name.\n");
    printf("Press 2 to update Mobile number.\n");
    printf("Press 3 to update Email id.\n");
    printf("Press 4 to update Address.\n");
    printf("Press 5 to update DOB.\n");
    printf("Press 6 to update password.\n");
    printf("Press 0 to go back\n");
    printf("Enter your choice : ");
    scanf("%d", &ch);
    if(ch==1){
        printf("Please enter your new name : ");
        char name[20];
        scanf("%d", &temp);
        scanf("%[^\n]", &name);
        while(fread(&u1, sizeof(u1), 1, fp1)){
            if(strcmp(u1.name , name)){
                fwrite(&u1, sizeof(u1), 1, fp2);
            }
        }
        strcpy(u2.name , name);
        fwrite(&u2, sizeof(u2), 1, fp2);
        fclose(fp2);
        fclose(fp1);
        int del = remove(filename);
        rename("copy.bin", filename);
        printf("Name succesfully updated.\n");
    }
    else if(ch==2){
        printf("Please enter your new mobile number : ");
        unsigned long long contact;
        scanf("%llu", &contact);
        while(fread(&u1, sizeof(u1), 1, fp1)){
            if(u1.contact != contact){
                fwrite(&u1, sizeof(u1), 1, fp2);
            }
        }
        u2.contact = contact;
        fwrite(&u2, sizeof(u2), 1, fp2);
        fclose(fp2);
        fclose(fp1);
        int del = remove(filename);
        rename("copy.bin", filename);
        printf("Contact succesfully updated.\n");
    }
    else if(ch==3){
        printf("Please enter your new mail id : ");
        scanf("%d", &temp);
        char mailid[20];
        scanf("%[^\n]", &mailid);
        while(fread(&u1, sizeof(u1), 1, fp1)){
            if(strcmp(u1.mailid , mailid)){
                fwrite(&u1, sizeof(u1), 1, fp2);
            }
        }
        strcpy(u2.mailid , mailid);
        fwrite(&u2, sizeof(u2), 1, fp2);
        fclose(fp2);
        fclose(fp1);
        int del = remove(filename);
        rename("copy.bin", filename);
        printf("Email succesfully updated.\n");
    }
    else if(ch==4){
        printf("Please enter your new address : ");
        scanf("%d", &temp);
        char address[100];
        scanf("%[^\n]", &address);
        while(fread(&u1, sizeof(u1), 1, fp1)){
            if(strcmp(u1.address , address)){
                fwrite(&u1, sizeof(u1), 1, fp2);
            }
        }
        strcpy(u2.address , address);
        fwrite(&u2, sizeof(u2), 1, fp2);
        fclose(fp2);
        fclose(fp1);
        int del = remove(filename);
        rename("copy.bin", filename);
        printf("Address succesfully updated.\n");
    }
    else if(ch==5){
        printf("Enter your new DOB : ");
        int date, month, year;
        printf("Date : ");
        scanf("%d" , &date);
        printf("\nMonth : ");
        scanf("%d", &month);
        printf("\nYear : ");
        scanf("%d", &year);
       while(fread(&u1, sizeof(u1), 1, fp1)){
            if(u1.date != date || u1.month != month || u1.year != year){
                fwrite(&u1, sizeof(u1), 1, fp2);
            }
        }
        u2.date = date;
        u2.month = month;
        u2.year = year;

        fwrite(&u2, sizeof(u2), 1, fp2);
        fclose(fp2);
        fclose(fp1);
        int del = remove(filename);
        rename("copy.bin", filename);
        printf("DOB succesfully updated.\n");
    }
    else if(ch==6){
        printf("Enter your new PIN : ");
        char password[15];
        for(k=0; k<15; k++){
            ch1 = getch();
            password[k]=ch1;
            if(ch1!=13 && ch1!=8)     
                printf("*");
            if(ch1 == 13)
                break;
        }
        password[k]='\0';
        printf("\nYour new created PIN is : ");
        for(k=0; k<strlen(password); k++){
            printf("%c", password[k]);
        }
        while(fread(&u1, sizeof(u1), 1, fp1)){
            if(strcmp(u1.password , password)){
                fwrite(&u1, sizeof(u1), 1, fp2);
            }
        }
        strcpy(u2.password , password);
        fwrite(&u2, sizeof(u2), 1, fp2);
        fclose(fp2);
        fclose(fp1);
        int del = remove(filename);
        rename("copy.bin", filename);
        printf("\nPassword succesfully updated.\n");
    }
    else if(ch==0){
        fclose(fp1);
        fclose(fp2);
    }
    
}
// void deposit( char username[]){
//     struct BMS u1;
//     FILE *fp;
//     char filename[20];
//     strcpy(filename, username);
//     fp = fopen(strcat(filename, ".txt"), "w+");
//     fread(&u1, sizeof(u1),1, fp);
//     int amount = 0;
//     printf("Enter the amount to be deposited : ");
//     scanf("%d", &amount);
//     u1.money = u1.money + amount;
//     printf("Money succesfully deposited.");
//     fwrite(&u1, sizeof(u1),1, fp);
//     fclose(fp);
// }
// void withdrawl( char username[]){
//     struct BMS u1;
//     FILE *fp;
//     char filename[20];
//     strcpy(filename, username);
//     fp = fopen(strcat(filename, ".txt"), "w+");
//     fread(&u1, sizeof(u1),1, fp);
//     int amount = 0;
//     printf("Enter the amount to be withdrawn : ");
//     scanf("%d", &amount);
//     fread(&u1, sizeof(u1), 1, fp);
//     if(u1.money<amount){
//         printf("Not enough money to withdraw.");
//     }
//     else{
//         u1.money = u1.money - amount;
//         printf("Money succesfully withdrawn.");
//         fwrite(&u1, sizeof(u1),1, fp);
//     }
    
//     fclose(fp);
// }
int main()
{
    system("cls");
    struct BMS u1[N];
    int choice;
    int i = 0;
    while (5)
    {
        printf("\t\t\t\tWELCOME TO THE BANK MANAGEMENT SYSTEM\n");
        printf("\t\t\t\t1.Create new account\n");
        printf("\t\t\t\t2.Login into existing account\n");
        printf("\t\t\t\t6.Exit\n");
        printf("\nEnter Your Choice : ");
        scanf("%d", &choice);
        if (choice == 1)
        {
            create_acc();
        }
        else if (choice == 2)
        {
            login();
        }
        else if (choice == 6){

        }
    }
    //printf("Thanks For Coming !!");
    return 0;
}

Answer 1

在写入之前，您需要查找文件的开头。否则，它将在您停止读取的位置写入更新的记录，而不是覆盖原始记录。

void deposit( char username[]){
    struct BMS u1;
    FILE *fp;
    char filename[20];
    strcpy(filename, username);
    fp = fopen(strcat(filename, ".txt"), "wb+");
    fread(&u1, sizeof(u1),1, fp);
    int amount = 0;
    printf("Enter the amount to be deposited : ");
    scanf("%d", &amount);
    u1.money = u1.money + amount;
    printf("Money succesfully deposited.");
    fseek(fp, 0, SEEK_SET);
    fwrite(&u1, sizeof(u1),1, fp);
    fclose(fp);
}