A file represents a sequence of bytes on the disk where a group of related data is stored. You can say, File is a storage area for data. It is ready made structure.
To write a C program, in order to create a file or read data from a file, we have to establish a buffer area. That is created using following syntax :
FILE *fp;
Where fp is a pointer that points a buffer area and FILE is written in uppercase. Here, fp indicates the begining of the buffer area.
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To read name and roll of a student, first we have to open the exam.dat file in read mode that is "r" and check if the file exists or not. If it exits, we will retrieve the content from the file using fscanf and display it using printf.
Here is the program.
#include<stdio.h>
#include<stdlib.h>
int main()
{
char name[20]; //It will copy the name from the file
int roll; //It will copy the roll no. from the file
FILE *fp; //fp denotes the starting of buffer area.
fp=fopen("exam.dat","r"); //fp will store the exam.dat file and opens in read mode
if(fp==NULL) //if there is no file
{
printf("File doesnot exits");
}
else
{
fscanf(fp,"%s,%d",name,&roll); //copy the name and roll
printf("Name=%s, Roll No.=%d",name,roll); //display whatever it gets from the file
}
fclose(fp); //it will close the buffer area
return 0;
}
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