File Handling in c
1.What is File handling in C ?
Ans: File handling in C is the process in which we create, open, read, write, and close operations on a file. C language provides different functions such as fopen(), fwrite(), fread(), fprintf(), etc. to perform input, output, and many different C file operations in our program.
Syntax : *ptr=fopen("filename","Mode")
| Mode | Description |
| r | Opens an existing text file for reading |
| W | Opens a file for writing. If it doesn't exist, then a new file is created. Writing starts from the beginning of the file. |
| a | Opens a text file for writing in appending mode. If it does not exist, then a new file is created. The program will start appending content to the existing file content. |
| This mode will open a text file for both reading and writing | |
| w+ | Opens a text file for both reading and writing. It first truncates the file to zero length If it exists, otherwise creates a file If it does not exist. |
| a+ | Opens a text file for both reading and writing. It creates the file if it does not exist. The reading will start from the beginning but writing can only append to file. |
Various Functions of file handling in c.
1. fputc() : This function is used to insert a single character in the file.
2. fputs () : This function is used to insert a string in a file.
3. fgetc() : This function is used to print the first character of a file
4. fgets() : This function is used to print the first string or a string of specific given size.
1. WAP to open a file.
#include <stdio.h>
#include <stdlib.h>
int main()
{
FILE* fptr;
fptr = fopen("filename.txt", "r");
if (fptr == NULL)
{
printf("The file is not opened. The program will "
"now exit.");
exit(0);
}
return 0;
}
2. WAP to create a file and write and close it.
#include <stdio.h>
#include <stdlib.h>
int main()
{
int num;
FILE *fptr;
fptr = fopen("program.txt","w");
if(fptr == NULL)
{
printf("Error!");
exit(1);
}
printf("Enter num: ");
scanf("%d",&num);
fprintf(fptr,"%d",num);
fclose(fptr);
return 0;
}
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