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CS 476/576
Systems Programming
Fall 2011
Midterm Exam

Time 2 & 1/2 hours
Open Book & Notes

 

 

 

Login:

 

Name:

Question 1:  25 points

 

The following commands lists the information about faculty group:

% ypcat group | egrep "^faculty:"

faculty:*:13:ajay,ibl,gpd,jrcrouch,grosch,mukka,olariu,cmo,pothen,price,toida,wilson,zeil,zubair,mln,brunelle,maly,rgupta,dkaneko,webgrade

What is the output of the next shell script?

 

groupfaculty.sh

#!/bin/sh

ypcat group | egrep “^faculty:” | tr ":" "\n" | tail -1 | tr "," "\n"

 

 

 

 

 

 

 

 

 

 

 

 

As you can see there are some faculty members who are not listed in the output of above script, e.g. wahab.

Write a script called  missingfaculty  that lists all those faculty that are missing from the output of the above script.

For example, my implementation produces:

% missingfaculty

bsympson

cboyle

chengapp

dranjan

jdm

jhe

kjohnso

kmaly

mweigle

nadeem

nikos

sji

taustin

wahab

yaohang

 

missingfaculty:


 

Question 2:  25 points

The command who shows an entry for each  login at the current host.

Write a program called whoname to list the full name of each login.

Here is an example:

% hostname

vega

% who

ibl      pts/2        2011-09-19 11:32 (ip24-254-195-222:S.3)
ibl      pts/3        2011-09-19 11:32 (ip24-254-195-222:S.4)
ibl      pts/4        2011-09-19 11:32 (ip24-254-195-222:S.5)
ibl      pts/5        2011-09-19 11:32 (ip24-254-195-222:S.6)
ibl      pts/6        2011-09-19 11:32 (ip24-254-195-222:S.7)
ibl      pts/7        2011-09-19 11:32 (ip24-254-195-222:S.0)
ibl      pts/13       2011-09-19 13:10 (dhcp-132.cs.odu.edu)
cs476    pts/14       2011-10-21 17:54 (dhcp-154.cs.odu.edu)
ibl      pts/12       2011-09-25 12:39 (ip24-254-195-222:S.8)
ibl      pts/15       2011-09-19 11:32 (ip24-254-195-222:S.1)
kpadia   pts/17       2011-10-23 19:12 (dhcp-72.cs.odu.edu)
pchodibo pts/18       2011-10-23 19:30 (wsip-98-190-61-27.hr.hr.cox.net)
ibl      pts/19       2011-09-19 11:32 (ip24-254-195-222:S.2)
zeil     pts/22       2011-10-02 15:27 (:1111.0)
mln      pts/9        2011-09-29 14:30 (dhcp-24.cs.odu.edu)
cs476    pts/29       2011-10-21 21:24 (dhcp-154.cs.odu.edu)
cs476    pts/31       2011-10-21 19:03 (dhcp-154.cs.odu.edu)
khaled   pts/32       2011-10-23 17:51 (dhcp-152.cs.odu.edu)
tlavang  pts/34       2011-10-23 21:42 (tejaswini-pc.odu.edu)

 

 

% whoname

cs476 grader
Dr. Irwin Levinstein
Khaled Almahallawy
kalpesh padia
Michael Nelson
pavan chodiboina
tejaswini lavang
Steven J. Zeil

%

 

 

 whoname

 

Question 3: 10 points

 

Write a curses program called   decorate.c   to  use “*” to frame the tty as shown.

Assume the tty has  20 rows and 80 columns.

 

decoratecap.jpg

decorate.c

Question 4: 20 points

 

 

Modify the  largecircle.c  program (partially listed below, use the provided spaces to write the missing code)  to draw the largest possible circle centered at  the click point  inside the drawing area.

 

For example; here is a snapshot of my implementation:

 

largecirclesfig.jpg

 

 

 

largecircle.c:

 

main(argc,argv)

int argc;

char **argv;

{

    Display *display;

    Window root, window;

    long fgcolor, bgcolor;

    int screen, pointx, pointy ;

    long eventmask = ButtonPressMask|ExposureMask|KeyPressMask;

    XEvent event;

    XGCValues gcval;

    GC draw;

    Colormap cmap;

    XColor color, ignore;

    char *colorname = "Red";

 

 

 

 

 

    display = XOpenDisplay(argv[1]);

    root = RootWindow(display,screen = DefaultScreen(display));

    fgcolor = BlackPixel(display,screen);

    bgcolor = WhitePixel(display,screen);

    window = XCreateSimpleWindow(display,root,0,0,800,800,2,fgcolor,bgcolor);

 

    cmap = DefaultColormap (display, screen);

    XAllocNamedColor(display, cmap, colorname, &color, &ignore);

    fgcolor = color.pixel;

    gcval.foreground = fgcolor;

    gcval.background = bgcolor;

    draw = XCreateGC(display,window,GCForeground|GCBackground,&gcval);

 

    XSelectInput(display,window,eventmask);

    XMapWindow(display,window);

 

    for (;;) {

     XWindowEvent(display,window,eventmask,&event);

     switch (event.type) {

       case Expose:

         XClearWindow(display,window);

         break;

      


 

case ButtonPress:

            pointx = event.xbutton.x;

            pointy = event.xbutton.y;

            XDrawPoint (display,window,draw, pointx, pointy);

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

         break;

          case KeyPress:

            exit(0);

      

     }

    }

}

 

 

Question 5: 20 points

 

The following program  xmbuttons  (partially  listed below, use the provide spaces to write your code) creates a motif  interface with a single button (Quit button).

Modify the program to add 3 more buttons labeled:

 

missingfaculty

whoname

decorate

 

to execute these commands.

We  would like each command displays its output inside its own xterm window.

To execute a command inside an xterm, we use:

% xterm –e command

For example:

% xterm –e ls –lt

creates an xterm, display the output of ls –lt, and then the xterm disappears.

To force the  xterm to  stay t for 60 seconds before it disappears, we  will use the following program called xcmd.

The xcmd  program executes the command, sleep 60 seconds and then exits.

 

xcmd.c:

 

main (int argc, char *argv[])
{
char cmd[100];
int i;
for (i=1; i< argc; i++) {
     strcat(cmd, argv[i]);
     strcat(cmd, " ");
}
system(cmd);
sleep(10);
}

For example, we can use this program as follows:

 

% xterm –e xcmd  ls –lt &

 

use  this xcmd to invoke the three programs in the xmbuttons.

 

xmbuttons:

 

void quitCallback ( Widget w, XtPointer clientData, XtPointer callData );

 

 

void main ( int argc, char **argv )
{
     Widget shell, commands,  quit;

     XtAppContext app;
     shell=XtAppInitialize(&app,"Xecute",NULL,0,&argc,argv,NULL,NULL,0);
     commands=XtVaCreateManagedWidget("commands",xmRowColumnWidgetClass,shell,

     XmNnumColumns, 3, XmNorientation, XmHORIZONTAL,  NULL );
     quit=XtVaCreateManagedWidget("Quit",xmPushButtonWidgetClass,commands,NULL,0);

 

 

 

 

 

 

 

 

 

 

     XtAddCallback ( quit, XmNactivateCallback, quitCallback, NULL);

 

 

 

 

 

 

 

 

 

 

 

 

      XtRealizeWidget ( shell );
      XtAppMainLoop ( app );
}

 

void quitCallback ( Widget w, XtPointer clientData, XtPointer callData )
{
      exit ( 0 );
}