Error: case 1 should not be repeated

Question

1.00/5 (2 votes)

See more:

The ID no: in case1 should be not repeated..[e.g when ID:1 is enter and save in text file 1 is not allowed anymore to enter...]
please help me with my error to fix...

C++

#include<iostream>
#include<conio.h>
#include<string.h>
#include<stdlib.h>
#include<iomanip>

using namespace std;
main(){
       
       FILE *ptr;
       FILE *tptr;
       char wb[100];
       int idn, sidn,idFromFile;
       int ch, xidn;
       char menu;
       bool exist;
       
       system("cls");
        
       cout&lt;&lt;"Menu\n\n";
       cout&lt;&lt;"1. add\n";
       cout&lt;&lt;"2. view\n";
       cout&lt;&lt;"3. del\n";	   
	   cout&lt;&lt;"Choice: "; 
       cin&gt;&gt;ch;
	   
	   switch (ch){
              case 1:
                   {
                   ptr = fopen("add.txt", "a+");
                   if(ptr == NULL)
                          {
                          cout&lt;&lt;"\n\nFILE COULD NOT BE OPENED!";
                          }
                   else{
                        
                       /* the error start here*/
                        ifstream ViewLogin(ptr);
                        
                        cout&lt;&lt;"\nID: ";
                        cin&gt;&gt;idn; 
                        //cin.ignore(); //xidn = ptr.idn;
                        getline(ViewLogin, idnFromFile);
                        while(idn == idnFromFile)
                        {
                                  cout&lt;&lt;"\nID EXIST!";
                                  cout&lt;&lt;"\nID: ";
                                  cin&gt;&gt;idn;           
                        }
                        //if(
                        cout&lt;&lt;"\twebsite: "; cin&gt;&gt;wb;  
                        fprintf(ptr,"%d\n%s\n", idn, wb);
                        fclose(ptr);                        
                        }
                                 getch();
                                 goto repeat;
                    }                        
              case 2:
                   {
                   ptr = fopen("add.txt", "r");
                   if(ptr == NULL){
                          cout&lt;&lt;"\n\nFILE COULD NOT BE OPENED!";
                          }
                   else{
                        char xwb[100];
                        int xidn;
                        cout&lt;&lt;"Search ID: "; cin&gt;&gt;sidn;
                        
                        while(!feof(ptr)){
                                          fscanf(ptr,"%d%s\n", &idn, wb);
                                        if(sidn == idn){
                                                 xidn = idn;
                                                 strcpy(xwb, wb); 
                                                
                                                 }
                                        else{
                                             cout&lt;&lt;"ID NOT EXIST!";
                                             }
                        } 
                        cout&lt;&lt;"\nInfo\n";
                        cout&lt;&lt;"ID:"&lt;&lt;"\t"&lt;&lt;xidn&lt;&lt;endl;
                        cout&lt;&lt;"Website: "&lt;&lt;"\t\t"&lt;&lt;xwb&lt;&lt;endl;
                                
                        fclose(ptr);          
                      
                        }                                                
                   getch();
                   goto repeat;
                   }    
                        
             case 3:
                        {
                        ptr = fopen("add.txt", "r");
                        int del;
                        if(ptr == NULL){
                               cout&lt;&lt;"\n\nFILE COULD NOT BE OPENED!";
                               }
                        else{
                             
                        while(!feof(ptr))
                        {
                             fscanf(ptr,"%d%s\n", &idn, wb);
                                                              
                        cout&lt;&lt;"Info\n";
                        cout&lt;&lt;"ID:"&lt;&lt;"\t\t\t"&lt;&lt;idn&lt;&lt;endl;
                        cout&lt;&lt;"website: "&lt;&lt;"\t\t"&lt;&lt;wb&lt;&lt;endl;
                       
                          }
                             cout&lt;&lt;" delete all records? 1 - YES, 2 - NO\n"; 
                             cin&gt;&gt;del;
                             if(del == 1){
                                    ptr = fopen("add.txt", "w");
                                    if(ptr == NULL){
                                           cout&lt;&lt;"\n\nFILE COULD NOT BE OPENED!";
                                           }
                                    else{
                                         fprintf(ptr,"");
                                         }
                                    }
                             else if(del == 2){
                                               goto repeat;
                                               }
                             else{
                                  cout&lt;&lt;"Wrong Input!";
                                  goto repeat;
                                  }
                                  fclose(ptr);
                                  }
                             getch();
                             goto repeat;
                             }                  
                   //case 4:
                    default:
                            {
                            cout&lt;&lt;"Wrong choice!";
                            getch();
                            
                            goto repeat;
                            }}
                            
                    repeat:
                    cout&lt;&lt;"\nReturn to Main Menu? [Y/N]";
                    cin&gt;&gt;menu;
                    if((menu == 'Y')||(menu == 'y')){
                             return main();
                             }
                    if((menu == 'N')||(menu == 'n')){
                             return 0;
                             }
getch();
}

[edit]Code block added, HTML characters encoded - OriginalGriff[/edit]
[edit]Clean Subject and Question body - johny10151981[/edit]

Posted 16-Jan-12 6:37am

reikuxian

Updated 16-Jan-12 14:08pm

Mohibur Rashid

v3

Add a Solution

Comments

Sergey Alexandrovich Kryukov 16-Jan-12 12:42pm

The question is not answerable because this is not a question, just a code dump. No question, no explanation...
--SA

Albert Holguin 17-Jan-12 12:44pm

Your question is not clear...

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Mohibur Rashid · Answer 1 · 2012-01-16T14:22:00

Solution 1

There is few stupidity(I am sorry I used that word but it is what it is) in your program.
1. You used goto statement. Its correct syntax, nothing harm to learn. But I read some experts suggestion to avoid <goto> by all means. No matter how complex the algorithm is you must have a better way to solve without goto statement
2. The big bang: You recursive your main . Never do that.

When you say main menu it does not mean main function. You know how to use while loop. so figure it out how you can iterate the entire process.

read switch-case statement again. read about how break statement is used in switch-case if you still have problem comeback again

Posted 16-Jan-12 14:22pm

Mohibur Rashid

Comments

Albert Holguin 17-Jan-12 12:44pm

+5, good advice

JackDingler 17-Jan-12 17:32pm

And 'ch' needs to updated to a new value to get it to trigger a different case statement.

Beelzebub is responsible for getting the ANSI committee approval of the goto statement. No other explanation rings true....

JackDingler 17-Jan-12 17:33pm

Maybe Loki... :)

Mohibur Rashid 17-Jan-12 23:51pm

haha, I never knew that. But in assembly its a big deal, hard to avoid :)

Emilio Garavaglia 18-Jan-12 3:06am

The reason why goto is there is that the only way to code a finite state machine without introducing fuzzy logic to bypass it.

There are no devils, loki or whatever religious reasons. Just well precise technical reasons.

Goto is the only readable way to escape more than one block (have you ever need to escape from two nested for loops? For one you have "break", for two you can either introducing a meaningless variable to force the exit condition or use a goto. There are entire programming school that consider the first practice more harmuful than the second.

Please stop blaming goto without reasons.
In these context goto-s are fine. The problem is a misuse of break statement in the switch.

If you are interesten in a more neutral analysys of what goto-s are for, read this: http://david.tribble.com/text/goto.html

Mohibur Rashid 18-Jan-12 4:08am

First of all nobody is blaming goto.

But use of goto creates unstructured form of programming and also can be confusing in big applications.

About Skipping the outer loop using break: still there is solution for that. Using flag you can easily go out of outer loop.

I dont know anything about loki, I tried to read on wiki but I dont understand the new add that has no escape :o. Anyway as far my intelligent says if I try to create assembly code from c all break will be translated as goto statemen

Emilio Garavaglia 18-Jan-12 4:38am

Johny, please, at least READ THE LINK I posted down-to the end.

I know about the use of flags, and I spoke of it in my comment as well (so what is your comment adding?)

But I also know that the use of 20 flags is worst than the use of a goto.

That said, I perfectly understand your point. But please also understand that there is not "science" behind that. Just only a matter of TASTE! (and please also understant my post was in answeer to Jack, not to you!)

It is true that a BAD use of GOTO can lead to unreadable code, but this fact is tautologically true for whatever statement, logic, or programming pattern you want / like to invent.
And that's not what I was talkmig about

Mohibur Rashid 18-Jan-12 4:52am

I will do that :)

JackDingler 18-Jan-12 9:22am

I understand how you may feel the way you do. I started out programming business applications in TurboBasic back in the 80s. In those days, the goto statement and the endless headaches that went with them, were thr norm. Even then, I quickly came to understand that gosubs were far superior, and when got my first C compiler and learned to use functions instead gotos, I never looked back.

It's my experience that it is hard to write clean structured code with gotos, regardless of philosophical attachment folks might have for it.

If you need 20 flag variables to break out of a while loop, you're doing it wrong. Putting in a goto, doesn't turn bad code into good code.

I thought you were arguing that you might need one test to break out of a while loop, I didn't know that you commonly need 20.

You should be putting more code into discrete functions. It will make your code easier to maintain.

Emilio Garavaglia 18-Jan-12 11:15am

At least red the link I posted ...................
If I have 20 nested loop I have to go out (Please don't focus to the number 20: I can say 2 with exactly the same consequence), nesting into function to use exception is just another way to do the same thing.

Admit that goto is there for a reason: There are problem domains where things cannot be decided into a pre-given set of strictures, whatever the set of structure is. It not a problem of "code readability" but of computation theory.

I can write a program with no if-s, just for
It will be certainly unreadable. But that -to me- it's not a good reason to bash for (or if), but to bash a bad structure choice.

The same is true for goto-s.
Instead of bash goto, look how the same code looks like without, then decide what reads better.
Believing or not, there are problem domains (most likely not the one you and Djiksta worked on...) where goto looks better.
The fact you didn't ever encounter them doesn't make them nonexistent.

JackDingler 18-Jan-12 12:24pm

I intend to read the link. didn't have much time this morning or now...

I have to say, the concept of a twenty level nested statement troubles me.

I used to write code that nested into multiple layers many years ago. I've learned a lot since then. For the last decade I've found that if I'm going past two, then it's because I haven't thought the problem out well enough.

If you're comfortable with gotos, and they fit your thinking pattern, by all means keep using them.

Mohibur Rashid 18-Jan-12 20:34pm

I remember a program with 8 nested for loop. I wrote that to solve 8 queen problem at first year when I started learning programming. It was the worst solution made by me for 8 queen and its a very good example for me of bad programming.

JackDingler 19-Jan-12 13:23pm

That's a good article.

It leaves out a C++ case where objects that handle their own resources are created on the stack, and thus an exit from a function can be made at any time with a simple return statement.

This eliminates the need for any of the mechanisms listed in the examples.
Further it provides cleaner code than any in the examples.

JackDingler 19-Jan-12 13:35pm

Back when I was programming in CP/M and DOS, I did worry more if I was using too many variables. Eliminating a variable or too reduced swaps to the registers, and could show significant performance increases.

Today, an argument over the overhead of one simple counter or boolean in context of the goto, seems a bit like arguing over how many angels can dance on the head of a pin.

reikuxian 18-Jan-12 10:00am

sorry guys for the disturb i just cant fix the error im having difficulties..

JackDingler 18-Jan-12 12:25pm

You have to change the value of 'ch' somewhere, to get the switch statement to hit a different case. So long as it remains == '1', you'll keep hitting the same case statement.