Thread: Text analysis problems - need help!

Can anyone please help?

I've been given the problem:

Write a C program that reads text from an input file, converts
any upper case letters to lower case, and writes the resulting text to an output file.

this is what i've got so far:

#include <stdio.h>
#include <ctype.h>

main()
{
int c;

while ((c=getchar()) !=EOF)
putchar(to lower(c));
return 0;
}


but this reading characters from getchar, not an input file. Also how do i write them to an output file?

Thank you so much, Sarah x

Use fgetc and fputc

And fopen and fclose for opening and closing the file

Whereabouts exactly, and how?

Is ThIs Ok...

Code:

#include<stdio.h>
#include<stdlib.h>  /* for exit() function */
#include<ctype.h>

int main()
{
 char ch;
 FILE *in_ptr, *out_ptr;

if((in_ptr=fopen("infile.txt","rt"))==NULL)
 {
  printf("CANNOT OPEN INFILE TO READ - PROGRAM STOPPED!");
  exit(1);
  }

if((out_ptr=fopen("outfile.txt","wt"))==NULL)
 {
  printf("CANNOT OPEN OUTFILE TO WRITE - PROGRAM STOPPED!");
  exit(1);
  }

  while((ch=fgetc(in_ptr))!=EOF)
	  fputc(tolower(ch),out_ptr);

 fclose(in_ptr);
 fclose(out_ptr);
 printf("EnD oF pRoGrAm!\n\nNoW LoOk At ThE cOnTeNtS oF oUtFiLe.TxT\n"
		  "WiTh A tExT eDiToR... oR wRiTe AnOtHeR pRoGrAm To DiSpLaY iT tO\n"
		  "tHe ScReEn!!\a");
 return 0;

  } /* end main */

/* Create a test file "infile.txt" for the A:drive, or other directory as preferred:

"hI, sarAH! I HOPE I DON'T upset anybody by doing YOUR homework! HaVe yOU dEAlt with files bEForE!? Bye from BADGER..."

*/

Cheers from MiStErBaDgEr

No probs MisterBadger, at least it's got a bug in it to keep haz115 guessing

> Whereabouts exactly, and how
Your book / compiler manual pages

1. In the code of MisterBadger, the use of exit() is unnecessary. You could better use return to return a return value, since main is of type int.

2. If opening of out_ptr is not succesfull, you need to close in_ptr since that file did open succesfully.

Thank you everybody so much!

How could I modify the program so that instead of converting the characters, it copies all the lower case letters and white space characters to the output file, discarding all other characters?

I think it will be very similar to misterbadgers code, except for

while((ch=fgetc(in_ptr))!=EOF)
fputc(tolower(ch),out_ptr);

Would it be
while((ch=fgetc(in_ptr))!=EOF)
if (...........)?
fputc(..........)?

Lowercase characters run from 0x61 ('a') to 0x7A ('z') and space is 0x20 (' '), got these values from the ASCII table. So you could do something like this:

Code:

if ((ch >= 0x61 && ch <= 0x7A) || ch == 0x20)
    fputc (ch, out_ptr);

Thanks again,

OK last question.....

how could i get the program to read a file of words(assumed to be in lower case) and print out the the total number of words?

I guess i wouldn't need the output file, and have to declare and integer to count the words.

but how I could i count the words?

Mr Shiro said:

1. In the code of MisterBadger, the use of exit() is unnecessary. You could better use return to return a return value, since main is of type int.

2. If opening of out_ptr is not succesfull, you need to close in_ptr since that file did open succesfully.

By using the exit() function defined in stdlib.h open streams are closed before program termination. exit(1); in this case is the same as exit(EXIT_FAILURE); Hence my use of this function instead of return 0; at this point in the program.

(Does this redeem me for declaring ch as a "char" and not an "int" in my earlier post?!

Cheers folks, Badge

haz, did you get it to work? I have done this several times before if you still need help...Once you do it and see through how it works you'll realize how easy it is.

-kris