Help with File operations

Dear All,
My task is as follows:-
1. I have to open file :CAN.c

2. find preprocessor directive

3. If preprocessor directive is Capital then i have to convert it into Lower

Ex:- #include<CAN.c>---------------->#include<can.c>

4. write it into other file

so for i have done as follows:-

Code:

---

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

int main(int argc,char **argv)
{
  const int max=1024;
  int r=0,i;
  FILE *in,*out;
  in=fopen("C:\\Documents and Settings\\syg4kor\\Desktop\\Perl_Programming\\CAN.c","rb");
  out=fopen("C:\\Documents and Settings\\syg4kor\\Desktop\\Perl_Programming\\CAN_CPY.c","wb");
  char buff[max+3];

  if (argc!=3)
  {
    r=1;
    printf("usage: lower <src> <dest>\n");
  }
  else if ((in=fopen(argv[1],"rb"))==NULL)
    {
      r=2;
      printf("cannot open input-file!\n");
    }
    else if ((out=fopen(argv[2],"wb"))==NULL) // Output file will be overwritten when exists !!!
      {
        r=3;
        printf("cannot open output-file!\n");
        }
      else
      {
        while (!feof(in))
        {
          buff[0]=0;
          fgets(buff,max,in);

          for (i=0;i<max && buff[i]!=NULL && &buff[i]!='\r' && buff[i]!='\n' && (buff[i]==' ' || buff[i]=='\t');i++);
          if (buff[i]=='#')
          {
            for (i=i+1;i<max && buff[i]!=NULL && buff[i]!='\r' && buff[i]!='\n';i++)
            {
              buff[i]=tolower(buff[i]);
            }
          }

          fputs(buff,out);
          }

        fclose(out);
      }

      fclose(in);

  return 0;
}

---

But i am getting following errors in highleghed line:

1. error C2446: '!=' : no conversion from 'int' to 'char *'

2. error C2040: '!=' : 'char *' differs in levels of indirection from 'int'

can anybody help me..actually i am learning C programming using this sight..this sight really very helpfull for learning C..i am thankful to all of you

Code:

---

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

int main(int argc,char **argv)
{
  const int max=1024;
  int r=0,i;
  FILE *in,*out;
  in=fopen("C:\\Documents and Settings\\syg4kor\\Desktop\\Perl_Programming\\CAN.c","rb");
  out=fopen("C:\\Documents and Settings\\syg4kor\\Desktop\\Perl_Programming\\CAN_CPY.c","wb");
  char buff[max+3];

  if (argc!=3)
  {
    r=1;
    printf("usage: lower <src> <dest>\n");
  }
  else if ((in=fopen(argv[1],"rb"))==NULL)
    {
      r=2;
      printf("cannot open input-file!\n");
    }
    else if ((out=fopen(argv[2],"wb"))==NULL) // Output file will be overwritten when exists !!!
      {
        r=3;
        printf("cannot open output-file!\n");
    }
      else
      {
        while (!feof(in))
        {
          buff[0]=0;
          fgets(buff,max,in);

          for (i=0;i<max && buff[i]!=NULL && &buff[i]!='\r' && buff[i]!='\n' && (buff[i]==' ' || buff[i]=='\t');i++);
          if (buff[i]=='#')
          {
            for (i=i+1;i<max && buff[i]!=NULL && buff[i]!='\r' && buff[i]!='\n';i++)
            {
              buff[i]=tolower(buff[i]);
            }
          }

          fputs(buff,out);
      }

        fclose(out);
      }

      fclose(in);

  return 0;
}

---

Can you catch the errors highlighted in RED?

Thanks manav it is working...

Quote:

---

Originally Posted by manav

Code:

---

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

int main(int argc,char **argv)
{
  const int max=1024;
  int r=0,i;
  FILE *in,*out;
  in=fopen("C:\\Documents and Settings\\syg4kor\\Desktop\\Perl_Programming\\CAN.c","rb");
  out=fopen("C:\\Documents and Settings\\syg4kor\\Desktop\\Perl_Programming\\CAN_CPY.c","wb");
  char buff[max+3];

  if (argc!=3)
  {
    r=1;
    printf("usage: lower <src> <dest>\n");
  }
  else if ((in=fopen(argv[1],"rb"))==NULL)
    {
      r=2;
      printf("cannot open input-file!\n");
    }
    else if ((out=fopen(argv[2],"wb"))==NULL) // Output file will be overwritten when exists !!!
      {
        r=3;
        printf("cannot open output-file!\n");
    }
      else
      {
        while (!feof(in))
        {
          buff[0]=0;
          fgets(buff,max,in);

          for (i=0;i<max && buff[i]!=NULL && &buff[i]!='\r' && buff[i]!='\n' && (buff[i]==' ' || buff[i]=='\t');i++);
          if (buff[i]=='#')
          {
            for (i=i+1;i<max && buff[i]!=NULL && buff[i]!='\r' && buff[i]!='\n';i++)
            {
              buff[i]=tolower(buff[i]);
            }
          }

          fputs(buff,out);
      }

        fclose(out);
      }

      fclose(in);

  return 0;
}

---

Can you catch the errors highlighted in RED?

---

I have rectifed the errors..but i am not getting correct result...

present:- Output file successufully created in present directory with empty

required:- Output file should creat as copy of original with

all Upper preprocessor directives replaced with lower preprocessor directives
ex:- #include<CAN.h>------>#include<can.h>

Code:

---

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

int main(int argc,char **argv)
{
  const int max=1024;
  int r=0,i;
  FILE *in,*out;
  in=fopen("C:\\Documents and Settings\\syg4kor\\Desktop\\Perl_Programming\\CAN.c","rb");
  out=fopen("C:\\Documents and Settings\\syg4kor\\Desktop\\Perl_Programming\\CAN_CPY.c","wb");
  char buff[max+3];

  if (argc!=3)
  {
    r=1;
    printf("usage: lower <src> <dest>\n");
  }
  else if ((in=fopen(argv[1],"rb"))==NULL)
    {
      r=2;
      printf("cannot open input-file!\n");
    }
    else if ((out=fopen(argv[2],"wb"))==NULL) // Output file will be overwritten when exists !!!
      {
        r=3;
        printf("cannot open output-file!\n");
        }
      else
      {
        while (!feof(in))
        {
          buff[0]=0;
          fgets(buff,max,in);

          for (i=0;i<max && buff[i]!='0' && buff[i]!='\r' && buff[i]!='\n' && (buff[i]==' ' || buff[i]=='\t');i++);

          if (buff[i]=='#')
          {
            for (i=i+1;i<max && buff[i]!='0' && buff[i]!='\r' && buff[i]!='\n';i++)
            {
              buff[i]=tolower(buff[i]);
            }
          }

          fputs(buff,out);
          }

        fclose(out);
      }

      fclose(in);

  return 0;
}

---

Code:

---

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

int main(int argc,char **argv)
{
    const int max=1024;
    int r=0,i;
    FILE *in,*out;
    char buff[max+3];

    if (argc!=3)
    {
        r=1;
        printf("usage: lower <src> <dest>\n");
    }
    else if ((in=fopen(argv[1],"rb"))==NULL)
    {
        r=2;
        printf("cannot open input-file!\n");
    }
    else if ((out=fopen(argv[2],"wb"))==NULL) // Output file will be overwritten when exists !!!
    {
        r=3;
        printf("cannot open output-file!\n");
    }
    else
    {
        while (!feof(in))
        {
            buff[0]=0;
            fgets(buff,max,in);

            for (i=0; i<max && buff[i] && buff[i]!='\r' && buff[i]!='\n' && (buff[i]==' ' || buff[i]=='\t'); i++);
            if (buff[i]=='#')
            {
                for (i=i+1;i<max && buff[i] && buff[i]!='\r' && buff[i]!='\n';i++)
                {
                    buff[i]=tolower(buff[i]);
                }
            }

            fputs(buff,out);
        }

        fclose(out);
        fclose(in);
    }

    return 0;
}

---

This is your code, can you spot the changes?
It also works fine!

Code:

---

for (i=0; i<max && buff[i] && buff[i]!='\r' && buff[i]!='\n' && (buff[i]==' ' || buff[i]=='\t'); i++);

---

This line doesn't do anything except waste CPU time (or is optimized out by the compiler). If you actually want it to do something, you need to get rid of the trailing semicolon and block in what you want to loop through.

ETA: Actually, it does pretty much ensure that i will not be 0 when you get to if(buff[i] == '#')