Programming Forums > Application Development > C

smoothdogg00 · Apr 15th, 2006, 9:27 PM

I am trying to print the contents of a file to a curses window. I have a main program that takes each line of a file and places it into an array of strings. I then pass that array to the following function, along with its number of items:

(Toggle Plain Text)

int showCurses(char *lineList[], int items)
{
  int j;

  initscr();
  noecho();
  getmaxyx(stdscr, row, col);

  for(j = 0; j < items; j++)
  {
    printw(lineList[j]);
  }

  refresh();
  while(getch() != 'e'){}
  endwin();

  return 0;
}

I know that the value of items is correct and that the array contains the contents of the file with each line being a string within the array.

So, what am I doing wrong? I have much more advanced things to do down the road, but I don't evne know how to get the file contents displayed! (In the future I'll have to be able to scroll up and down through the file.)

InfoGeek · Apr 15th, 2006, 9:37 PM

How are you calling the function?

smoothdogg00 · Apr 15th, 2006, 9:45 PM

showCurses(fileBuffer, i);, where: char *fileBuffer[1000] and int i. Within the showCurses function, I have checked the lineList for accurate data, which it shows when printed, and the same with items.

It shows me a blank screen and then, as expected, waits for me to press 'e' to exit the curses window.

grumpy · Apr 15th, 2006, 9:58 PM

I'm guessing that your lines don't contain end of line markers, so all of the printw() calls will write to the first line. Try changing the call to printw() in the loop to "printw("%s\n", lineList[j]);" or add a second line "printw("\n");" in the loop.

smoothdogg00 · Apr 15th, 2006, 10:02 PM

After adding the '\n' character to each line, I am still seeing the same output (sometimes a blank screen, sometimes a few random lines throughout the screen, depending on the file read). Since nobody is seeing an error immediately, perhaps someone could compile it and see what its doing for them?

grumpy · Apr 15th, 2006, 10:29 PM

We would also need the code that you call the function with. Are your strings zero terminated?

smoothdogg00 · Apr 15th, 2006, 10:34 PM

Here is my entire program. My strings, I am assuming, are zero terminated since I did a malloc(strlen(str2) + 1) and then strcpy(str1, str2).

(Toggle Plain Text)

#include <stdio.h>
#include <string.h> /* for strlen, strcpy */
#include <stdlib.h> /* for malloc         */
#include <ncurses.h>

#define NUM_STRINGS 1000

FILE *Fp;
int row, col;

int main (int argc, char *argv[])
{
  char *fileBuffer[NUM_STRINGS]; /* array of pointers */
  char tempString[BUFSIZ]; /* size of input buffer defined in stdio.h */
  int i = 0; /* line counter */

  printf("argc = %d\n", argc);

  if (argc < 2)
    {
      printf("There was no file name on the command line\n");
      return 0;
    }

  if((Fp = fopen(argv[argc - 1], "r")) == NULL)
    {
      printf("Couldn't open file %s for reading\n", argv[argc-1]);
      return 0;
    }

  printf("Opened file %s for reading\n", argv[argc-1]);
  
  while((i < NUM_STRINGS) && fgets(tempString, sizeof(tempString), Fp)) 
    {
      fileBuffer[i] = malloc(strlen(tempString) + 1);
      if (!fileBuffer[i]) 
	{
          printf("Can't allocate %d bytes for fileBuffer[%d]\n", 
                        strlen(tempString)+1, i);
          break;
	}
      strcpy(fileBuffer[i], tempString);
      // printf("%d: %s", i, fileBuffer[i]);
      i++;
    }

   showCurses(fileBuffer, i);

  return 0;
}

int showCurses(char *lineList[], int items)
{
  int j;

  initscr();
  noecho();
  getmaxyx(stdscr, row, col);

  for(j = 0; j < items; j++)
  {
    printw("%s\n", lineList[j]);
  }

  refresh();
  while(getch() != 'e'){}
  endwin();

  
  return 0;
}

InfoGeek · Apr 16th, 2006, 12:04 AM

Works for me except for the last line.

tested with:

(Toggle Plain Text)

hello
this is just a test
a few lines of text
delimeted by new line
hello
this is just a test
a few lines of text
delimeted by new line
hello
this is just a test
a few lines of text
delimeted by new line
hello
this is just a test
a few lines of text
delimeted by new line
hello
this is just a test
a few lines of text
delimeted by new line
hello
this is just a test
a few lines of text
delimeted by new line
hello
this is just a test
a few lines of text
delimeted by new line
hello
this is just a test
a few lines of text
delimeted by new line
hello
this is just a test
a few lines of text
delimeted by new line
nnnnn

output:

(Toggle Plain Text)

hello
this is just a test
a few lines of text
delimeted by new line
hello
this is just a test
a few lines of text
delimeted by new line
hello
this is just a test
a few lines of text
delimeted by new line
hello
this is just a test
a few lines of text
delimeted by new line
hello
this is just a test
a few lines of text
delimeted by new line
hello
this is just a test
a few lines of text
delimeted by new line
hello
this is just a test
a few lines of text
delimeted by new line
hellothis is just a testa few lines of textdelimeted by new linehellothis is just a testa few ln

smoothdogg00 · Apr 16th, 2006, 12:31 AM

It must have to do with the fact that I'm using Cygwin then...what are you using?

And did you compile it like this:

gcc file.c -lcurses -o -file

InfoGeek · Apr 16th, 2006, 1:24 AM

I'm on Linux using ncurses. I compiled it with:
gcc -Wall -lncurses -ofile file.c

Apr 15th, 2006, 9:27 PM	#1
smoothdogg00 Newbie Join Date: Mar 2006 Location: Maine Posts: 11 Rep Power: 0	Help with curses! (Beginner) I am trying to print the contents of a file to a curses window. I have a main program that takes each line of a file and places it into an array of strings. I then pass that array to the following function, along with its number of items: (Toggle Plain Text) int showCurses(char lineList[], int items) { int j; initscr(); noecho(); getmaxyx(stdscr, row, col); for(j = 0; j < items; j++) { printw(lineList[j]); } refresh(); while(getch() != 'e'){} endwin(); return 0; } int showCurses(char lineList[], int items) { int j; initscr(); noecho(); getmaxyx(stdscr, row, col); for(j = 0; j < items; j++) { printw(lineList[j]); } refresh(); while(getch() != 'e'){} endwin(); return 0; } I know that the value of items is correct and that the array contains the contents of the file with each line being a string within the array. So, what am I doing wrong? I have much more advanced things to do down the road, but I don't evne know how to get the file contents displayed! (In the future I'll have to be able to scroll up and down through the file.)

Apr 15th, 2006, 9:37 PM	#2
InfoGeek Professional Programmer Join Date: Jun 2005 Location: India, The great. Posts: 435 Rep Power: 4	How are you calling the function? __________________ PFO - My daily dose of technology.

Apr 15th, 2006, 10:34 PM	#7
smoothdogg00 Newbie Join Date: Mar 2006 Location: Maine Posts: 11 Rep Power: 0	Here is my entire program. My strings, I am assuming, are zero terminated since I did a malloc(strlen(str2) + 1) and then strcpy(str1, str2). (Toggle Plain Text) #include <stdio.h> #include <string.h> /* for strlen, strcpy / #include <stdlib.h> / for malloc / #include <ncurses.h> #define NUM_STRINGS 1000 FILE Fp; int row, col; int main (int argc, char argv[]) { char fileBuffer[NUM_STRINGS]; /* array of pointers / char tempString[BUFSIZ]; / size of input buffer defined in stdio.h / int i = 0; / line counter / printf("argc = %d\n", argc); if (argc < 2) { printf("There was no file name on the command line\n"); return 0; } if((Fp = fopen(argv[argc - 1], "r")) == NULL) { printf("Couldn't open file %s for reading\n", argv[argc-1]); return 0; } printf("Opened file %s for reading\n", argv[argc-1]); while((i < NUM_STRINGS) && fgets(tempString, sizeof(tempString), Fp)) { fileBuffer[i] = malloc(strlen(tempString) + 1); if (!fileBuffer[i]) { printf("Can't allocate %d bytes for fileBuffer[%d]\n", strlen(tempString)+1, i); break; } strcpy(fileBuffer[i], tempString); // printf("%d: %s", i, fileBuffer[i]); i++; } showCurses(fileBuffer, i); return 0; } int showCurses(char lineList[], int items) { int j; initscr(); noecho(); getmaxyx(stdscr, row, col); for(j = 0; j < items; j++) { printw("%s\n", lineList[j]); } refresh(); while(getch() != 'e'){} endwin(); return 0; } #include <stdio.h> #include <string.h> /* for strlen, strcpy / #include <stdlib.h> / for malloc / #include <ncurses.h> #define NUM_STRINGS 1000 FILE Fp; int row, col; int main (int argc, char argv[]) { char fileBuffer[NUM_STRINGS]; /* array of pointers / char tempString[BUFSIZ]; / size of input buffer defined in stdio.h / int i = 0; / line counter / printf("argc = %d\n", argc); if (argc < 2) { printf("There was no file name on the command line\n"); return 0; } if((Fp = fopen(argv[argc - 1], "r")) == NULL) { printf("Couldn't open file %s for reading\n", argv[argc-1]); return 0; } printf("Opened file %s for reading\n", argv[argc-1]); while((i < NUM_STRINGS) && fgets(tempString, sizeof(tempString), Fp)) { fileBuffer[i] = malloc(strlen(tempString) + 1); if (!fileBuffer[i]) { printf("Can't allocate %d bytes for fileBuffer[%d]\n", strlen(tempString)+1, i); break; } strcpy(fileBuffer[i], tempString); // printf("%d: %s", i, fileBuffer[i]); i++; } showCurses(fileBuffer, i); return 0; } int showCurses(char lineList[], int items) { int j; initscr(); noecho(); getmaxyx(stdscr, row, col); for(j = 0; j < items; j++) { printw("%s\n", lineList[j]); } refresh(); while(getch() != 'e'){} endwin(); return 0; }

Apr 16th, 2006, 12:04 AM	#8
InfoGeek Professional Programmer Join Date: Jun 2005 Location: India, The great. Posts: 435 Rep Power: 4	Works for me except for the last line. tested with: (Toggle Plain Text) hello this is just a test a few lines of text delimeted by new line hello this is just a test a few lines of text delimeted by new line hello this is just a test a few lines of text delimeted by new line hello this is just a test a few lines of text delimeted by new line hello this is just a test a few lines of text delimeted by new line hello this is just a test a few lines of text delimeted by new line hello this is just a test a few lines of text delimeted by new line hello this is just a test a few lines of text delimeted by new line hello this is just a test a few lines of text delimeted by new line nnnnn hello this is just a test a few lines of text delimeted by new line hello this is just a test a few lines of text delimeted by new line hello this is just a test a few lines of text delimeted by new line hello this is just a test a few lines of text delimeted by new line hello this is just a test a few lines of text delimeted by new line hello this is just a test a few lines of text delimeted by new line hello this is just a test a few lines of text delimeted by new line hello this is just a test a few lines of text delimeted by new line hello this is just a test a few lines of text delimeted by new line nnnnn output: (Toggle Plain Text) hello this is just a test a few lines of text delimeted by new line hello this is just a test a few lines of text delimeted by new line hello this is just a test a few lines of text delimeted by new line hello this is just a test a few lines of text delimeted by new line hello this is just a test a few lines of text delimeted by new line hello this is just a test a few lines of text delimeted by new line hello this is just a test a few lines of text delimeted by new line hellothis is just a testa few lines of textdelimeted by new linehellothis is just a testa few ln hello this is just a test a few lines of text delimeted by new line hello this is just a test a few lines of text delimeted by new line hello this is just a test a few lines of text delimeted by new line hello this is just a test a few lines of text delimeted by new line hello this is just a test a few lines of text delimeted by new line hello this is just a test a few lines of text delimeted by new line hello this is just a test a few lines of text delimeted by new line hellothis is just a testa few lines of textdelimeted by new linehellothis is just a testa few ln __________________ PFO - My daily dose of technology.

Apr 16th, 2006, 1:24 AM	#10
InfoGeek Professional Programmer Join Date: Jun 2005 Location: India, The great. Posts: 435 Rep Power: 4	I'm on Linux using ncurses. I compiled it with: gcc -Wall -lncurses -ofile file.c __________________ PFO - My daily dose of technology.

Apr 15th, 2006, 9:45 PM	#3
smoothdogg00 Newbie Join Date: Mar 2006 Location: Maine Posts: 11 Rep Power: 0	showCurses(fileBuffer, i);, where: char *fileBuffer[1000] and int i. Within the showCurses function, I have checked the lineList for accurate data, which it shows when printed, and the same with items. It shows me a blank screen and then, as expected, waits for me to press 'e' to exit the curses window.

Apr 15th, 2006, 9:58 PM	#4
grumpy Programming Guru Join Date: Jun 2005 Location: Adelaide, South Australia Posts: 1,260 Rep Power: 5	I'm guessing that your lines don't contain end of line markers, so all of the printw() calls will write to the first line. Try changing the call to printw() in the loop to "printw("%s\n", lineList[j]);" or add a second line "printw("\n");" in the loop.

Apr 15th, 2006, 10:02 PM	#5
smoothdogg00 Newbie Join Date: Mar 2006 Location: Maine Posts: 11 Rep Power: 0	After adding the '\n' character to each line, I am still seeing the same output (sometimes a blank screen, sometimes a few random lines throughout the screen, depending on the file read). Since nobody is seeing an error immediately, perhaps someone could compile it and see what its doing for them?

Apr 15th, 2006, 10:29 PM	#6
grumpy Programming Guru Join Date: Jun 2005 Location: Adelaide, South Australia Posts: 1,260 Rep Power: 5	We would also need the code that you call the function with. Are your strings zero terminated?

Apr 16th, 2006, 12:31 AM	#9
smoothdogg00 Newbie Join Date: Mar 2006 Location: Maine Posts: 11 Rep Power: 0	It must have to do with the fact that I'm using Cygwin then...what are you using? And did you compile it like this: gcc file.c -lcurses -o -file

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Programming Forums > Application Development > C

Help with curses! (Beginner)