having trouble opening file and converting all lowercase letters to uppercase letters

[Jeff Dill]

I'm writing a program that asks user to enter a file to be opened and then convert all lower case letters to uppercase letters and then display the file. the way i have my program write now, it doesnt seem to go go into the toUpper function and when it displays the file, my program crashes. Please help, Thank you.

#include <stdio.h>
#include <stdlib.h>


int main()
{
    FILE *inFile;
    char fileName[30];
    char toUpper(char);
    
    printf("\nPlease enter the file to be opened: ");
    gets(fileName);
    inFile = fopen(fileName, "r");
    
    
    if (inFile == NULL)
    {
               printf("\nThe file %s was not successfully opened.", fileName);
               printf("\nPlease check that you have typed in the correct file.\n");              
               system("PAUSE");
               exit(1);
    }
    
    printf("\nThe file has been opened\n");
    system("PAUSE");
    
    void convert(char fileName[])
    {
         int i=0;
         
         while (fileName[i] != '\0');
         {
               fileName[i] = toUpper(fileName[i]);
               i++;
         }
    }
    
    while (fscanf(inFile,"%s", fileName) != NULL)
    printf("%s", fileName);
   
  
  system("PAUSE");    
  return 0;
}


char toUpper(char letter)
{
     if( letter>= 'a' && letter <= 'z')
         return (letter - 'a' +'A');
     else
         return (letter);
}

[whiteflags]

How are you even getting a build? You must not be compiling according to any standard:

C:\Users\Josh2>gcc -Wall -ansi -pedantic jeff.c
jeff.c: In function 'main':
jeff.c:27:5: warning: ISO C forbids nested functions [-pedantic]
jeff.c:27:5: warning: ISO C90 forbids mixed declarations and code [-pedantic]
jeff.c:38:42: warning: comparison between pointer and integer [enabled by defaul
t]

Move the convert function out of main()'s scope.
Then call convert in main() instead.
Stop using filename to do everything; that makes it really confusing to read the code.

Unless you have to make your own toUpper, I would just use the one in the ctype.h library.

Edit: Also, be careful of mistakes like this.

  while (fileName[i] != '\0');

[vart]

FAQ > Why gets() is bad / Buffer Overflows - Cprogramming.com
FAQ > Get a line of text from the user/keyboard (C) - Cprogramming.com

Check return value fscanf - C++ Reference

Functions in C - Cprogramming.com