Question

我试图从“users.txt”文件验证用户名，邮件和密码，我试图使用fgets，但是当我运行它时，它无法识别信息，当我尝试打印实际验证的内容时，原来它从fgets函数中得到的字符串完全出乎意料。

来自users.txt的数据：

牛仔
jn@gmail.com
jj123
阿尔弗雷
alf@gmail.com
somepass
robt
rob@gmail.com
rob111

据我所知，fgets返回字符串，直到找到\ n字符或它到达文件末尾。我从printf那里得到了什么：

jj123 jj123 jj123 robt robt robt rob111 （空值）（空）

代码： `

void login(bool is_logged_in)
{
    printf("enter your name\n");
    string name_session = GetString();

    printf("enter your mail:\n");
    string mail_session = GetString();

    printf("enter your password:\n");
    string password_session = GetString();

    FILE *users_file;
    char getstring[100];
    users_file = fopen("users.txt", "r");
    if (users_file != NULL)
    {
        while (feof(users_file) == 0)
        {
            //added this to check what I was actually getting from file
            string text1 = fgets(getstring,100,users_file);
            string text2 = fgets(getstring,100,users_file);
            string text3 = fgets(getstring,100,users_file);
            printf("%s",text1);
            printf("%s",text2);
            printf("%s",text3);
            //3 times because the if statement is checking 3 strings

            if ((fgets(getstring,100,users_file) == name_session ) &&
                (fgets(getstring,100,users_file) == mail_session) &&
                (fgets(getstring,100,users_file) == password_session))
            {
                is_logged_in = true;
                fclose(users_file);
                menu();
            }
        }
        printf("You've failed your log in.\n");
        fclose(users_file);
        menu();
    }
    else
    {
        printf("¡¡ERROR!!: there's been a problem and the program will now exit.\n");
    }
}

`

Answer 1

使用fstream代替

#include <iostream>
#include <string>
#include <fstream>
using namespace std;
int main(){
   string line;
   ifstream file("users.txt");
   if(!file){
     cout<<"file do not exist!\n";
     return 0;
   }
   while(getline(file,line)){
     cout<<line<<endl;
   }
}

如何验证.txt文件中的用户数据？ C ++

1 个答案: