Enter password, hide by "*".

This is a discussion on Enter password, hide by "*". within the C++ Programming forums, part of the General Programming Boards category; I write a little program, just want to test getch() function. When you enter password, they dont display in monitor, ...

  1. #1
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    Enter password, hide by "*".

    I write a little program, just want to test getch() function.
    When you enter password, they dont display in monitor,
    instead of "*". It 's running OK.
    But some statements look very stupid,
    please give some improvement!
    thanks.

    PHP Code:
    #include <iostream.h>
    #include <conio.h>
    #include <stdlib.h>

    void main()
    {
        
    char m[3]={'t','o','y'};   //to save original password.
        
    char n[3]={'0','0','0'};  //initialize your entering password.
        
    cout<<"Please enter 3 bit password: "<<flush;  
        
    n[0]=getch();            //enter word ,but no display it              
        
    cout<<"*"<<flush;    //when enter word, display “*”
        
    n[1]=getch();
        
    cout<<"*"<<flush;
        
    n[2]=getch();
        
    cout<<"*"<<flush;
        if(
    m[0]==n[0]&&m[1]==n[1]&&m[2]==n[2])   //stupid code!
        
    {
            
    cout<<"password correct,welcome!"<<endl
        
         }
        else
        {
            
    cout<<"error."<<endl;
        }

    system("pause");    //pause running window.
    return;


    Last edited by toysoldier; 08-12-2004 at 05:28 AM.

  2. #2
    Sweet
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    it looks ok to me besides the
    Code:
    void main()
    main should always return a int
    Code:
    int main(void)
    {
      //code
      return 0;
    }
    Woop?

  3. #3
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    @ prog-bman :
    OH, it's a tip "int instead of void" or rule ?

    How about this statement:
    if(m[0]==n[0]&&m[1]==n[1]&&m[2]==n[2]) //stupid code!
    Thanks.
    Last edited by toysoldier; 08-12-2004 at 05:42 AM.

  4. #4
    mustang benny bennyandthejets's Avatar
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    That looks fine.
    benforbes@optusnet.com.au
    Microsoft Visual Studio .NET 2003 Enterprise Architect
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  5. #5
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    >>OH, it's a tip "int instead of void" or rule ?
    It is a rule. The C++ standard requires main to return an integer except in very specialized implementations where it imposes no restrictions. The general rule of thumb is that if you do not know whether or not you are using such an implementation, you are not and thus the relaxed rules do not apply to you. As such, instead of saying that every time somebody uses void as the return type for main, most helpful souls will simply tell you that returning void from main is illegal or wrong or evil or something similar for the sake of brevity.

  6. #6
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    @ Princeton :
    Thanks,
    I think I have learning a lot of valuable knowledge after entered this great forum.
    Thanks every friend !

  7. #7
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    You will probably learn about control loops in the near future. They will provide you with the techniques to "clean up" the sections of the code that you felt uncomfortable with.

  8. #8
    Toaster Zach L.'s Avatar
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    One other thing.
    <iostream.h> is no longer standard, use <iostream> and the std namespace (putting 'using namespace std;' after your includes is the easiest to start with).
    <stdlib.h> is standard C, but it is good to get in the habbit of using <cstdlib> in C++ along with the namespace.
    Just be aware that <conio.h> is a non-standard header and you may or may not find it if you change compilers.

    Code:
    #include <iostream>
    #include <conio.h>
    #include <cstdlib> 
    
    using namespace std;

  9. #9
    Carnivore ('-'v) Hunter2's Avatar
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    >>if(m[0]==n[0]&&m[1]==n[1]&&m[2]==n[2]) //stupid code!
    An easier way to do this would be:
    Code:
    char m[4]="toy";   //4th character is '\0' (null). 
    char n[4]="000";  //same as above.
    
    (...)
    
    if(strcmp(m, n) == 0)   //compare the strings m and n
    {...}
    else
    {...}
    
    **OR**
    
    char m[3] = {'t','o','y'};
    char n[3] = {'0','0','0'};
    
    (...)
    
    if(memcmp(m, n, 3) == 0)   //compare 3 elements of m and n
    {...}
    else
    {...}
    Hope this helps!
    Just Google It. √

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  10. #10
    I'm less than sure.... abyssphobia's Avatar
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    ok your code corrected will be like this:

    #include <iostream>
    #include <cstdlib>
    #include<conio.h>

    using namespace std;

    int main()
    {

    char m[3]={'t','o','y'}; //to save original password.

    char n[3]={'0','0','0'}; //initialize your entering password.
    cout<<"\n"
    cout<<"\nPlease enter 3 bit password: "<<flush;

    n[0]=getch(); //enter word ,but no display it

    cout<<"*"<<flush; //when enter word, display “*”

    n[1]=getch();

    cout<<"*"<<flush;
    n[2]=getch();
    cout<<"*"<<flush;
    if(m[0]==n[0]&&m[1]==n[1]&&m[2]==n[2]) //stupid code!
    {
    cout<<"password correct,welcome!"<<endl;

    }
    else
    {
    cout<<"error."<<endl;
    }

    system("pause"); //pause running window.
    return 0;

    }


    but I ran it,mmm the pasword is toy!!!!

  11. #11
    Registered User linuxdude's Avatar
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    just to let you know that isn't a 3 bit password

  12. #12
    Carnivore ('-'v) Hunter2's Avatar
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    I like the original code better. Slightly less standard, but it's code-tagged (Actually PHP tagged, but that's better than nothing), and the spacing is more intuitive. Abyssphobia, use code tags!
    Just Google It. √

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  13. #13
    I'm less than sure.... abyssphobia's Avatar
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    yeah it's 4 bit pasword!!! zero is null duh!!mmm sorry a little distraction
    mmm code tags?
    How?? I read the post but I didnt got it. =(
    you know, Im gonna print the post to look it better=)

    regards,

    Abyss

  14. #14
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    No its a 3 bit. 0 - 1 - 10 - 11. 11==3.
    Child who knows C++
    Using Borland C/C++ Compiler 5.5 (Command Line Version)

  15. #15
    Registered User linuxdude's Avatar
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    what, no.
    Code:
    #include <limits.h>
    number_of_bits=CHAR_BIT*(strlen(m));
    number_of_bits+=CHAR_BIT;
    plust your code doesn't have enough room for a terminating '\0'(if I enter three characters)

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