如何在 C++ 中删除密码屏蔽

Question

我正在制作用户名和密码。在此之前，当我输入 backspace 时，不是擦除密码，而是 backspace 输入了一些东西，我想出了使用 ASCII，但我不知道脚本删除密码。

int a=0, i=0;
char uname[10], c=' '; 
char pword[10], code[10];
char user[10]="user";
char pass[10]="pass";

a:

system("cls");  
printf("\n\n\t\t\t======================================");
printf("\n\n\t\t\t|   STUDENT REPORTING SCORE SYSTEM    |");
printf("\n\n\t\t\t======================================");
printf("\n\n\t\t\t===========  LOGIN FIRST  ============");
printf("\n\n\n\t\t\t\tENTER USERNAME : ");
scanf("%s", &uname); 
printf("\n\n\t\t\t\tENTER PASSWORD : ");
while(i<10)
{
    pword[i]=getch();
    c=pword[i];
    if(c==13) break;
    else if(c==8)
    //here is the blank
    else printf("*");
    i++;
}
pword[i]='\0';
i=0;

if(strcmp(uname,"user")==0 && strcmp(pword,"pass")==0)
{
    printf("\n\n\n\t\t\tWELCOME TO STUDENT REPORTING SCORE SYSTEM\n\t\t\t\t  LOGIN IS SUCCESSFUL");
    printf("\n\n\n\t\t\t    Press any key to continue...");
    getch();    
}
else
{
    printf("\n\n\n\t\t\t   SORRY !!!! LOGIN IS UNSUCESSFUL");
    getch();
    goto a;     
}

我不知道该在//here is the blank 中写什么。所以当我使用a-=2时，它并不想删除*，也不会输入任何内容。

Answer 1

我稍微修改了你的代码。
在我的系统上，getch() 已被弃用，因此我使用 _getch() 代替。在 printf 之后，我在下一个 _getch() 得到了一个 '\0' 字符。所以我必须用if (c == '\0') continue; 线忽略它。

要删除'*' 字符，您必须打印"\b \b"（\b 后退一个字符。' ' 会覆盖'*' 和'\b' 再次后退）。

如果用户输入 10 个字符作为密码，则代码中存在缓冲区溢出。您必须为最后一个 '\n' 字符分配 10 + 1 长度数组。

我认为您应该使用 std::string 而不是 char* 并从代码中删除未使用的变量。

希望对你有帮助。

bool login(std::string& username, std::string& password)
{
    username = "";
    password = "";
    char c = ' ';

    system("cls");
    printf("\n\n\t\t\t======================================");
    printf("\n\n\t\t\t|   STUDENT REPORTING SCORE SYSTEM    |");
    printf("\n\n\t\t\t======================================");
    printf("\n\n\t\t\t===========  LOGIN FIRST  ============");
    printf("\n\n\n\t\t\t\tENTER USERNAME : ");
    std::cin >> username;
    printf("\n\n\t\t\t\tENTER PASSWORD : ");

    while (true)
    {
        c = _getch();
        if (c == '\r') break;
        if (c == '\0') continue;
        if (c == '\b')
        {
            if (password.length() > 0)
            {
                password.pop_back();
                printf("\b \b");
            }
        }
        else
        {
            printf("*");
            password.push_back(c);
        }
    }

    _getch(); // Read the extra '\0'

    if (username == "user" && password == "pass")
    {
        printf("\n\n\n\t\t\tWELCOME TO STUDENT REPORTING SCORE SYSTEM\n\t\t\t\t  LOGIN IS SUCCESSFUL");
        return true;
    }
    else
    {
        printf("\n\n\n\t\t\t   SORRY !!!! LOGIN IS UNSUCESSFUL");
        return false;
    }
}

int main()
{
    while (true)
    {
        std::string username = "";
        std::string password = "";
        auto successLogin = login(username, password);
        if (successLogin)
            break;

        _getch(); // Press any key to continue...
    }

    return 0;
}

Answer 2

void login()
c:

system("cls");    

char choice='Y', input, passChar[100],userChar[100];

    for (int i=0; i<100; userChar[i++]=0);

while(choice=='Y'){ 
    system ("cls");
    cout<<"\n\n\t\t\t======================================";
    cout<<"\n\n\t\t\t|   STUDENT SCORE REPORTING SYSTEM    |";
    cout<<"\n\n\t\t\t======================================";
    cout<<"\n\n\t\t\t===========  LOGIN FIRST  ============";
    cout<<"\n\n\n\t\t\t\tENTER USERNAME : ";
    cin.getline(userChar,100);
    system("cls");

    cout<<"\n\n\t\t\t======================================";
    cout<<"\n\n\t\t\t|   STUDENT SCORE REPORTING SYSTEM    |";
    cout<<"\n\n\t\t\t======================================";
    cout<<"\n\n\t\t\t===========  LOGIN FIRST  ============";
    cout<<"\n\n\n\t\t\t\tENTER PASSWORD: ";

for (int i=0;;i++)
{
  input=getch();
  if ((input!=8)&&(input!=13))
  { 
    passChar[i]=input;
  }

  else if (input==8)
  i-=2;
  else if (input==13)
  break;
  system("cls");
  cout<<"\n\n\t\t\t======================================";
  cout<<"\n\n\t\t\t|   STUDENT SCORE REPORTING SYSTEM    |";
cout<<"\n\n\t\t\t======================================";
cout<<"\n\n\t\t\t===========  LOGIN FIRST  ============";
cout<<"\n\n\n\t\t\t\tENTER PASSWORD: ";
for (int j=0; j<i+1; j++)
    cout<<"*";


}
cout<<endl;
if (!strcmp(userChar, "admin"))
{
    cout<<"UserName correct!\n";
}
else
    cout<<"Username incorrect!\n";
if (!strcmp(passChar, "pass"))
{
    cout<<"Password correct!\n";                  
}
else
cout<<"Password incorrect!\n";
if ((!strcmp(userChar,"admin"))&&(!strcmp(passChar, "pass")))
{
    cout<<"Access Granted!";
    getch();        
    return;                             
                                                   }                      
else 
    cout<<"Acess denied!\n";
cout<<"Do you want to try again? Y/N : ";
cin>>choice;
choice=toupper(choice);
cin.ignore(100,'\n');
for (int i=0; i<100; userChar[i++]=0);
for (int i=0; i<100; passChar[i++]=0);

}}