C Programming Tutorial
Writing File : fprintf() function
The fprintf() function is used to write set of characters into file. It sends formatted output to a stream.
Syntax:
int fprintf(FILE *stream, const char *format [, argument, ...])
Example:
#include <stdio.h>
main(){
FILE *fp;
fp = fopen("file.txt", "w");//opening file
fprintf(fp, "Hello file by fprintf...\n");//writing data into file
fclose(fp);//closing file
}
Reading File : fscanf() function
The fscanf() function is used to read set of characters from file. It reads a word from the file and returns EOF at the end of file.
Syntax:
int fscanf(FILE *stream, const char *format [, argument, ...])
Example:
#include <stdio.h>
main(){
FILE *fp;
char buff[255];//creating char array to store data of file
fp = fopen("file.txt", "r");
while(fscanf(fp, "%s", buff)!=EOF){
printf("%s ", buff );
}
fclose(fp);
}
Output:
Hello file by fprintf...
C File Example: Storing employee information
Let's see a file handling example to store employee information as entered by user from console. We are going to store id, name and salary of the employee.
#include <stdio.h>
void main()
{
FILE *fptr;
int id;
char name[30];
float salary;
fptr = fopen("emp.txt", "w+");/* open for writing */
if (fptr == NULL)
{
printf("File does not exists \n");
return;
}
printf("Enter the id\n");
scanf("%d", &id);
fprintf(fptr, "Id= %d\n", id);
printf("Enter the name \n");
scanf("%s", name);
fprintf(fptr, "Name= %s\n", name);
printf("Enter the salary\n");
scanf("%f", &salary);
fprintf(fptr, "Salary= %.2f\n", salary);
fclose(fptr);
}
Output:
Enter the id
131
Enter the name
Rama
Enter the salary
150000
Now open file from current directory. For windows operating system, go to TC\bin directory, you will see emp.txt file. It will have following information.
emp.txt
Id= 131
Name= Rama
Salary= 150000
EXAMPLE PROGRAM FOR FSCANF(), FPRINTF(), FTELL(), REWIND() FUNCTIONS IN C PROGRAMMING LANGUAGE:
This file handling C program illustrates how to read and write formatted data from/to a file.
#include <stdio.h>
int main ()
{
char name [20];
int age, length;
FILE *fp;
fp = fopen ("test.txt","w");
fprintf (fp, "%s %d", “cprogramming”, 31);
length = ftell(fp); // Cursor position is now at the end of file
/* You can use fseek(fp, 0, SEEK_END); also to move the
cursor to the end of the file */
rewind (fp); // It will move cursor position to the beginning of the file
fscanf (fp, "%d", &age);
fscanf (fp, "%s", name);
fclose (fp);
printf ("Name: %s \n Age: %d \n",name,age);
printf ("Total number of characters in file is %d", length);
return 0;
}
OUTPUT:
Name: cprogramming
Age: 31
Total number of characters in file is 15
