Solved

Ncurses/getch() issues

Posted on 2008-10-23
17
1,144 Views
Last Modified: 2013-11-15
I'm fairly new to C and have come to realize that conio.h isn't part of the standard ANSI C library. Unfortunately I have a data validation project assigned for class that can't really get done without something to capture characters on keypress. After some looking around ncurses seemed like the library to get so I did. Unfortunately now my output comes up quite funny.
I am using the gcc compiler via cygwin and using the netbeans IDE.

Attatched is a picture of the output.
I'm really at a loss of what to do at this point so any information would be helpful.

COLORS.h is just a header with a bunch of screen macro's.. CLS, LOCATE, PAUSE, ect...

/* 

 * File:   p4_c.c

 * Author: Admin

 *

 * Created on October 16, 2008, 2:31 PM

 */

 

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <CTYPE.H>

#include <COLORS.H>

#include <ncurses.h.lnk>

#define BACKSPACE putchar(8)

void paintscreen(),getdata(),prntrpt();

char * inptrtn(int fldlen,char type);

char* inptrtnstr(int fldlen);

char *inptrtnint(int fldlen);

char* inptrtnfloat(int fldlen);

int i;

char buffer[30];

struct name

{char first[15];

 char last[20];

};

struct

{struct name name;

 int credits;

 float GPA;

}student[3];

/*

 * 

 */

int main(int argc, char** argv) {

    paintscreen();

    while (strlen(student[i].name.first)!=0)

    {   getdata();

        PAUSE;

        i++;

        paintscreen();

    }

    return (EXIT_SUCCESS);

}

void paintscreen(){

    CLS;

    LOCATE(1,15);puts("Student Information Data Entry");

    LOCATE(3,1);puts("First Name:______________");

    LOCATE(5,1);puts("Last Name:____________________");

    LOCATE(7,1);puts("Credits:___");

    LOCATE(9,1);puts("GPA:_.__");

    LOCATE(3,12);

    strcpy(student[i].name.first,inptrtn(14,'a'));

}

void getdata(){

    char GPA;

    LOCATE(5,11);strcpy((student[i].name.last),inptrtn(19,'a'));

    LOCATE(7,9);student[i].credits=atoi(inptrtn(3,'i'));

    LOCATE(9,5);strcpy(GPA,inptrtn(1,'f'));

    strcat(GPA,".");

    LOCATE(9,7);strcat(GPA,inptrtn(2,'f'));

    student[i].GPA=atof(GPA);

}

char * inptrtn(int fldlen,char type){

    static char buffer[30];

    switch (type)

    {   case 'a':inptrtnstr(fldlen);break;

        case 'i':inptrtnint(fldlen);break;

        case 'f':inptrtnfloat(fldlen);break;

    }

    return buffer;

}

char * inptrtnstr(int fldlen){

    char c,d;

    int j=0;

    strcpy(buffer,"");

    while ((c=getch())!=13)

    {d=toupper(c);

     if (d>="A"&&d<='Z'||d=='.'||d=='-'||d==' '||d=='\'')

     {  buffer[j++]=c;putchar(c);

      if (j==fldlen)

         break;

     }

     if (c==8 && j!=0)

        {j--;BACKSPACE;}

         buffer[j]='\0';

    }

    return buffer;

}

char * inptrtnint(int fldlen){

    char c;

    int j;

    strcpy(buffer,"");

    while ((c=getch())!=13)

    {if (c>='0' && c<='9')

     {    buffer[j++]=c;putchar(c);

        if(j==fldlen)

            break;

     }

     if (c==8 && j!=0)

     {j--;

      BACKSPACE;

     }

     buffer[j]='\0';

    }

    return buffer;

    }   

char * inptrtnfloat(int fldlen){

    char c;

    int j;

    strcpy(buffer,"");

    while ((c=getch())!=13)

    {    if (fldlen=1)

        {if (c>=0&&c<=4)

            {  buffer[j++]=c;putchar(c);

                if (j==fldlen)

                 break;

            }

        }

         else {if (c>=0&&c<=9)

            {  buffer[j++]=c;putchar(c);

                if (j==fldlen)

                 break;

            }

              }

         if (c==8 && j!=0)

     {j--;

      BACKSPACE;

     }

         buffer[j]='\0';

    }

    return buffer;

}

void printrpt()

{int j=0;

 for (j=0;j<3;j++)

 {    printf("Name: %-15s %-20s\n",student[j].name.first,student[j].name.last);

      printf("Credits: %-3",student[j].credits);

      printf("GPA: %f",student[j].GPA);

 }

}

Open in new window

output.JPG
0
Comment
Question by:Aya861
17 Comments
 
LVL 45

Expert Comment

by:Kdo
ID: 22789055
Hi Aya861,

Where did the message "[Press Enter to close window]" come from?  I don't see it in your source code anywhere.


Kent
0
 
LVL 53

Expert Comment

by:Infinity08
ID: 22789101
Why do you get the student's first name inside the paintscreen function rather than in the getdata function ?

Inside getdata, you declare GPA as a single char, but you treat it as a string (array of char) further.

In inptrtnstr : "A" is not the same as 'A'. The first is a string literal, the second is a character literal. You want a character literal.
0
 
LVL 13

Expert Comment

by:numberkruncher
ID: 22789126
Is getch() returning ERR?

According to the documentation, getch() returns ERR when it is in non-blocking mode.

Try adding the following after paintscreen in your main function.

timeout(-300);
0
 

Author Comment

by:Aya861
ID: 22789175
Well the "A" was a mistake that I didn't catch as was declaring GPA as a single character and not a character array.

As for getting the student's first name in paintscreen, it should set me up to determine whether or not the enter key is pressed.

After fixing those 2 errors, paint screen occurs and then nothing. No keyboard entry is accepted :/
0
 

Author Comment

by:Aya861
ID: 22789241
Edit: The program isn't even locating back to 3,12. It looks like its getting hung up on this line right here.
LOCATE(3,12);

strcpy(student[i].name.first,inptrtn(14,'a'));

Open in new window

0
 
LVL 53

Expert Comment

by:Infinity08
ID: 22789243
You didn't initialize i nor the student array.
0
 
LVL 53

Expert Comment

by:Infinity08
ID: 22789260
Note that you also didn't call initscr() to set up the screen for curses, nor endwin() at the end.
0
 
LVL 53

Expert Comment

by:Infinity08
ID: 22789274
Also, you should probably use the curses output methods (like printw) instead of the stdio ones.
0
How your wiki can always stay up-to-date

Quip doubles as a “living” wiki and a project management tool that evolves with your organization. As you finish projects in Quip, the work remains, easily accessible to all team members, new and old.
- Increase transparency
- Onboard new hires faster
- Access from mobile/offline

 

Author Comment

by:Aya861
ID: 22789556
Is there any rule saying that I need to use curses screens? Student and i were initialized globally.

I'm only using ncurses for the getch() function at this point.
0
 
LVL 53

Accepted Solution

by:
Infinity08 earned 250 total points
ID: 22789602
>> Student and i were initialized globally.

They were declared globally. They were not initialized.


>> Is there any rule saying that I need to use curses screens?

You said you wanted to use curses :) That's not a rule. That's your choice.


>> I'm only using ncurses for the getch() function at this point.

It doesn't work like that ;) The usage of getch requires that curses has control over the screen.
0
 

Author Comment

by:Aya861
ID: 22789653
Doesn't a global integer variable automatically get initialized at 0? I mean I could initialize the character arrays to "" but I really don't think that'd do much. As for needing curses to be in control of the screen... well I didn't know about that. Will test that out and hope it works.
0
 
LVL 53

Expert Comment

by:Infinity08
ID: 22789766
>> Doesn't a global integer variable automatically get initialized at 0?

Yes, but why not do it explicitly ? For that matter, why have global variables at all ?
0
 

Author Comment

by:Aya861
ID: 22789781
I don't want to pass a pointer to a structure through like 9 different functions?
0
 

Author Comment

by:Aya861
ID: 22789830
Edit... I guess passing them to the 3 functions that use it wouldn't be that difficult... this was just the way the example was written and I didn't really think otherwise.
0
 
LVL 53

Expert Comment

by:Infinity08
ID: 22789835
>> I don't want to pass a pointer to a structure through like 9 different functions?

Only the functions that need it. So, basically, only the getdata and the printdata.

In any case, you should avoid global data as a general rule. It might seem easier at first, but it isn't, trust me. Function interfaces are best made explicit in their signature. Not only will that make code maintenance easier - it will also control the flow of data better, and only have data available where it's needed.
0
 

Author Comment

by:Aya861
ID: 22789903
I'm gradually learning this with some of my own code that isn't assigned as a project...
As for why I haven't checked the code yet... well I'm in Composition class right now and can't really open up my laptop to check.
0
 
LVL 53

Expert Comment

by:Infinity08
ID: 22789915
No problem. Take all the time you need :)
0

Featured Post

How to run any project with ease

Manage projects of all sizes how you want. Great for personal to-do lists, project milestones, team priorities and launch plans.
- Combine task lists, docs, spreadsheets, and chat in one
- View and edit from mobile/offline
- Cut down on emails

Join & Write a Comment

Suggested Solutions

Today companies are subjected to more-and-more data, and it won't stop any time soon.  But there are obvious opportunities for reducing data, particularly data duplicated among companies.
A high-level exploration of how our ever-increasing access to information has changed the way we do our jobs.
The viewer will learn how to pass data into a function in C++. This is one step further in using functions. Instead of only printing text onto the console, the function will be able to perform calculations with argumentents given by the user.
An overview on how to enroll an hourly employee into the employee database and how to give them access into the clock in terminal.

762 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

20 Experts available now in Live!

Get 1:1 Help Now