Finding, opening and closing a text file for reading C program example
Compiler: Visual C++ Express Edition 2005
Compiled on Platform: Windows Xp Pro with SP2
Header file: Standard
Additional library: none/default
Additional project setting: Set project to be compiled as C
Project -> your_project_name Properties -> Configuration Properties -> C/C++ -> Advanced -> Compiled As: Compiled as C Code (/TC)
Other info:
To do: Finding, opening and closing a text file for reading using C file input/output functions
To show: How to use the C file input/output functions in opening text file for reading
At the beginning there is no tkk1103.txt text file in C:
// Opening and closing file example
#include <stdio.h>
// SUCCESS = 0, FAIL = 1 using enum
enum {SUCCESS, FAIL};
int main (void)
{
FILE *fptr;
errno_t err = 0;
// the filename is tkk1103.txt and located in the C:\ folder. For other location, provide the full path
// e.g. "D:\\Myfolder\\test.txt etc
char filename[] = "C:\\tkk1103.txt";
// set the value reval to 0
int reval = SUCCESS;
// test opening file for reading
// if((fptr = fopen(filename, "r")) == NULL), using a secure version
err = fopen_s(&fptr, filename, "r");
// if fail...
if( err != 0)
{
printf("Cannot open %s.\n", filename);
reval = FAIL; //reset reval to 1
}
// if successful do...
else
{
printf("Opening the %s file successfully\n", filename);
// the program will display the address where the file pointer points to..
printf("The value of fptr pointer is: 0x%p\n", fptr);
printf("\n....file processing should be done here....\n");
printf("\nReady to close the %s file.\n", filename);
// close the file stream...
if(fclose(fptr) == 0)
printf("Closing the %s file successfully\n", filename);
}
return reval;
}
Output example:
Cannot open C:\tkk1103.txt.
Press any key to continue . . .
Then create a text file named tkk1103.txt ant put it under the C: and re-run the previous program. The output should be as shown below.
Opening the C:\tkk1103.txt file successfully
The value of fptr pointer is: 0x10310C30
....file processing should be done here....
Ready to close the C:\tkk1103.txt file.
Closing the C:\tkk1103.txt file successfully
Press any key to continue . . .