This is my attempt!

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Hello. I am having the hardest time getting my code to compile. My compiler tells me that there are conflicting types for convert and that there is a previous declaration to convert. I have not added any notation to the code as yet. Thanks for any help.

Code:

---

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

FILE *getOpen();
void inOut(FILE *);
void toUpper(char);
void convert(char);

int main()
{

  FILE *outFile;
 
  outFile = getOpen();
  inOut(outFile);
  fclose(outFile);
  printf("The File was successuflly written.\n");
 
  void convert(char);

  getch();
  return 0;
}

FILE *getOpen()
{
    FILE *fname;
    char name[13];
   
    printf("Enter a file name:  ");
    gets(name);
    fname=fopen(name, "w");

  if (fname == NULL)
  {
            printf("\nFailed to open the file %s.\n");
            exit(1);
  }
  return (fname);
}

void inOut(FILE *fname)
{
    int count;
    char line[81];
    printf("Please enter five lines of text:\n");
    for (count = 0; count < 5; count++)
    {
        gets(line);
        fprintf(fname, "%s\n", line);
       
    }
}

void convert(char line[81])
{
    int i=0;
   
    while (line[i] != '\0');
    {
          line[i] = toUpper(line[i]);
          i++;
    }
          return 0;
}
void toUpper(char letter)
{
    if( letter >= 'a' && letter <= 'z')
    return (letter - 'a' + 'A');
    else
    return (letter);
}

---

Code:

---

void convert(char);

---

Prototype for a function accepting a single character as an argument.

Code:

---

void convert(char line[81])
{
    int i=0;
   
    while (line[i] != '\0');
    {
          line[i] = toUpper(line[i]);
          i++;
    }
          return 0;
}

---

Implementation of a function which accepts an array of characters as an argument.

Not so good way...

Code:

---

void convert(char line[81])
{
    int i=0;
   
    while (line[i] != '\0');
    {
          line[i] = toUpper(line[i]);
          i++;
    }
          return 0;
}

---

Better way...

Code:

---

#include <string.h>
#incldue <ctype.h>

// prototype
void convert(char *line);

// implementation
void convert(char *line)
{
    int i=0;
    while (line[i] != '\0');
      {
          line[i] = toupper(line[i]);
          i++;
      }
    line[i] = 0;
    }

---

Arrays decay to pointers when passed into functions.
toupper() is a standard C-99 library function, no need to reinvent the wheel.

Thanks. This was very helpful! That pointer stuff gets me every time! I figured out my void prototype was using char instead of char[] as well. There are some really handy tools in the C library function!

Of course, I have run into a wall with printing the newly uppercased contents of the line[81]. Do I have to use a prototype function or can I just insert a fprints() under main() somehow? When I use the fprints(outFile, "%s", line[81]); my compiler says that it is the first use of line[81] even though the last two functions defined it!

Code:

---

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

FILE *getOpen();
void inOut(FILE *);
char convert(char *);

int main()
{

  FILE *outFile;
 
  outFile = getOpen();
  inOut(outFile);
  fclose(outFile);

  fprtints(outFile, "%s", line[81]);

  printf("The File was successuflly written.\n");
  char convert(char []);
  getch();
  return 0;
}

FILE *getOpen()
{
    FILE *fname;
    char name[13];
    printf("Enter a file name:  ");
    gets(name);
    fname=fopen(name, "w");


  if (fname == NULL)
  {
            printf("\nFailed to open the file %s.\n");
            exit(1);
  }
  return (fname);
}

void inOut(FILE *fname)
{
    int count;
    char line[81];
    printf("Please enter five lines of text:\n");
    for (count = 0; count < 5; count++)
    {
        gets(line);
        fprintf(fname, "%s\n", line);
       
    }
}

char convert(char *line)
{
    int i=0;
   
    while (line[i] != '\0');
    {
          line[i] = toupper(line[i]);
          i++;
    }
          return 0;
}

---

Ok, so let's see....

Code:

---


fclose(outFile);  //<----------This closes the file

fprtints(outFile, "%s", line[81]); //<-----------Now you try to write to a closed file with a made up function

---

File Ops FAQ

Quote:

---

Originally Posted by geustuser

Thanks. This was very helpful! That pointer stuff gets me every time! I figured out my void prototype was using char instead of char[] as well. There are some really handy tools in the C library function!

Of course, I have run into a wall with printing the newly uppercased contents of the line[81]. Do I have to use a prototype function or can I just insert a fprints() under main() somehow? When I use the fprints(outFile, "%s", line[81]); my compiler says that it is the first use of line[81] even though the last two functions defined it!

---

Way wrong...

Code:

---

  fprtints(outFile, "%s", line[81]);

---

This should work...

Code:

---

  fprintf(outFile, "%s\n", line);  // print to file
  printf("%s\n"",line);    // print to screen

---

When you keep including the size like that, the compiler thinks you are making a new variable...

I had to include char line[81] as a variable in main() to get it to accept the print feature but instead of the five strings of entered text back, I'm getting three nonsense characters. These do change with different inputs as file name and lines of text so it looks like data is being passed to the line[]. I'm thinking maybe a prototype function is the way to go. I tried that out using the line notation but it will not print any of the file. Both methods are in this code... I seriously appreciate your time and help with this!

Code:

---

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

FILE *getOpen();
void inOut(FILE *);
char convert(char *);
char textprint(char *);

int main()
{

  FILE *outFile;
  char line[81];
  outFile = getOpen();
  inOut(outFile);
 
  fclose(outFile);
 
  printf("The File was successuflly written.\n");
  char convert(char []);
  char textprint(char *line);
   
  fprintf(outFile, "%s\n", line);  // print to file
  printf("%s\n",line);
 
  getch();
  return 0;
}

FILE *getOpen()
{
    FILE *fname;
    char name[13];
    printf("Enter a file name:  ");
    gets(name);
    fname=fopen(name, "w");


  if (fname == NULL)
  {
            printf("\nFailed to open the file %s.\n");
            exit(1);
  }
  return (fname);
}

void inOut(FILE *fname)
{
    int count;
    char line[81];
    printf("Please enter five lines of text:\n");
    for (count = 0; count < 5; count++)
    {
        gets(line);
        fprintf(fname, "%s\n", line);
    }
}

char convert(char *line)
{
    int i=0;
   
    while (line[i] != '\0');
    {
          line[i] = toupper(line[i]);
          i++;
    }
          return 0;
}

char textprint(char *line)
{
    int i=0;
   
    while (line[i] != '\0');
    {
          printf("%s", line[i]);
          i++;
    }
          return (*line);
}

FILE *getOpen()
{
    FILE *fname;
    char name[13];
    printf("Enter a file name:  ");
    gets(name);
    fname=fopen(name, "w");


  if (fname == NULL)
  {
            printf("\nFailed to open the file %s.\n");
            exit(1);
  }
  return (fname);
}

void inOut(FILE *fname)
{
    int count;
    char line[81];
    printf("Please enter five lines of text:\n");
    for (count = 0; count < 5; count++)
    {
        gets(line);
        fprintf(fname, "%s\n", line);
    }
}

char convert(char *line)
{
    int i=0;
   
    while (line[i] != '\0');
    {
          line[i] = toupper(line[i]);
          i++;
    }
          return 0;
}

char textprint(char *line)
{
    int i=0;
   
    while (line[i] != '\0');
    {
          printf("%s", line[i]);
          i++;
    }
          return (*line);
}

---

Honestly?

Code:

---

 
  [B]fclose(outFile);[B]    YOU ARE CLOSING THE FILE HERE
 
  printf("The File was successuflly written.\n");
 
  char convert(char []); //<---------- WHAT ARE YOU TRYING TO DO HERE
  char textprint(char *line);<---------  AND HERE.....Function Tutorial
   
  fprintf(outFile, "%s\n", line);  // print to file  YOU ARE TRYING TO WRITE TO THE CLOSED FILE STILL

---

Look, we all want to help but you are just throwing code around and it doesn't seem like you are trying to learn anything. I suggest starting with the tutorials they have made on this site!!!

Sorry, bad post. I changed the order to be before the file is closed as shown below. Still getting three random characters for the printf(). Does the printf() work for what I'm trying to do?

Code:

---

int main()
{

  FILE *outFile;
  char line[81];

  outFile = getOpen();
  inOut(outFile);
  char convert(char []); 

  fprintf(outFile, "%s\n", line);  // print to file
  printf("%s\n",line);                // print to screen
 
  fclose(outFile);

  printf("The File was successuflly written.\n");
 
  getch();
  return 0;
}

---

Quote:

---

Originally Posted by geustuser

I had to include char line[81] as a variable in main() to get it to accept the print feature but instead of the five strings of entered text back, I'm getting three nonsense characters.

---

That line variable is different than the one you use in inOut. Since it's a local variable, and you don't initialize it or put any useful data in it, it contains garbage, hence your nonsense characters.

Quote:

---

I'm thinking maybe a prototype function is the way to go.

---

I don't know what you mean by this, and I'm not sure you do either. A prototype just tells the compiler about a function (parameters and return type), so it can make sure you use it right. This is only needed if you call the function before you define it (like how you call getOpen in main, but define getOpen after main). The compiler reads from top to bottom and only knows about stuff it's already seen (things above it in the file).

Code:

---

FILE *getOpen();
void inOut(FILE *);
char convert(char *);
char textprint(char *);


int main()
{

  FILE *outFile;
  char line[81];
  outFile = getOpen();
  inOut(outFile);
 
  fclose(outFile);
 
  printf("The File was successuflly written.\n");
  char convert(char []);
  char textprint(char *line);
   
  fprintf(outFile, "%s\n", line);  // print to file
  printf("%s\n",line);
 
  getch();
  return 0;
}

---

Those two red lines are prototypes, not function calls. Take them out. Never put a prototype inside a function. The belong where you have the others, above your functions (green text). Also, as I mentioned, the line variable in main is different from the one in inOut. You need to declare one in main, and pass it in to inOut. Note that line is declared as a single array of chars, thus it can only hold one line at a time. If you need to hold several lines, you need an array of array of chars:

Code:

---

int main()
{
    char line[5][81];  // declare line to be an array of 5 "lines", each "line" having room for 80 chars plus the terminating null.
    ...
    inOut(outFile, line);  // pass line into inOut
    convert(line[0]);  // converts the first line to upper case, do this for all lines, using a loop
}
...
void inOut(FILE *fname, char line[][81])
{
    int count;
    char line[81];
    printf("Please enter five lines of text:\n");
    for (count = 0; count < 5; count++)
    {
        fgets(line[count], 81, stdin);  // gets is bad, see the FAQ
        fprintf(fname, "%s\n", line);
    }
}

---

That should get you going for a bit.

The compiler is getting hung up on the InOut(outFile, line); because it has too many arguments. I made changes to update the array. Not sure if I did that right. Wow, there are so few things in life that make me feel so retarded as programming in C. I really appreciate all the direction I'm getting from your community!

Code:

---

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

FILE *getOpen();
void inOut(FILE *);
char convert(char *);

int main()
{

  FILE *outFile;
  char line[5][81];

  outFile = getOpen();
  inOut(outFile, line);
  convert(line[0]); 

  fprintf(outFile, "%s\n", line);  // print to file
  printf("%s\n",line);  // print to screen
 
  fclose(outFile);

  printf("The File was successuflly written.\n");
 
  getch();
  return 0;
}

FILE *getOpen()
{
    FILE *fname;
    char name[13];
    printf("Enter a file name:  ");
    gets(name);
    fname=fopen(name, "w");


  if (fname == NULL)
  {
            printf("\nFailed to open the file %s.\n");
            exit(1);
  }
  return (fname);
}

void inOut(FILE *fname, char line[][81])
{
    int count;
    char line[][81];
    printf("Please enter five lines of text:\n");
    for (count = 0; count < 5; count++)
    {
        fgets(line[count], 81, stdin);
        fprintf(fname, "%s\n", line);
       
    }
}

char convert(char *line)
{
    int i=0;
   
    while (line[i][] != '\0');
    {
          line[i][] = toupper(line[i][]);
          i++;
    }
          return 0;
}

---

Guestuser... stop guessing. Spend some time with the tutorials and manuals, you need to actually learn C...

Quote:

---

Originally Posted by geustuser

The compiler is getting hung up on the InOut(outFile, line); because it has too many arguments. I made changes to update the array. Not sure if I did that right. Wow, there are so few things in life that make me feel so retarded as programming in C. I really appreciate all the direction I'm getting from your community!

---

You clearly didn't learn anything from post #2, and you don't get what a prototype is actually for. You're cutting and pasting our suggestions literally, without thought to how it affects anything, and taking shots in the dark trying to fix it. We don't usually hand out big chunks of working code here, rather we point you in the right direction, and sometimes give you a swift kick in the butt to get you moving. You need to actually think about what you're doing. Until I see evidence of that, I refuse to help.

As everybody here has been suggesting, work your way through the tutorials we have on this site (if you can't find them, they're here: Cprogramming.com - Programming Tutorials: C++ Made Easy and C Made Easy), and Google around for some more. Also, I'm guessing you're in school, so read your class notes and textbooks. Go through all the sections in order, working through each example and exercise until you totally get it. You need to totally understand functions, arrays and file handling for this assignment, so make sure you really get that.

I seriously appreciate the help. Spot on, I'm trolling through tutorials right now. I definitely let this language go over my head. If I have any seriously valid problems I'll let you all know. Great community of people, thanks again.