File Examples

Examples of files in C Programming
C Program to read name and marks of students and store it in file
C Program to read name and marks of students and store it in file. If file already exists, add information to it.
C Program to write members of arrays to a file using fwrite()

Write a C program to read name and marks of n number of students from user and store them in a file

#include <stdio.h>
int main(){
   char name[50];
   int marks,i,n;
   printf("Enter number of students: ");
   scanf("%d",&n);
   FILE *fptr;
   fptr=(fopen("C:\\student.txt","w"));
   if(fptr==NULL){
       printf("Error!");
       exit(1);
   }
   for(i=0;i<n;++i)
   {
      printf("For student%d\nEnter name: ",i+1);
      scanf("%s",name);
      printf("Enter marks: ");
      scanf("%d",&marks);
      fprintf(fptr,"\nName: %s \nMarks=%d \n",name,marks);
   }
   fclose(fptr);
   return 0;
}

Write a C program to read name and marks of n number of students from user and store them in a file. If the file previously exits, add the information of n students.

#include <stdio.h>
int main(){
   char name[50];
   int marks,i,n;
   printf("Enter number of students: ");
   scanf("%d",&n);
   FILE *fptr;
   fptr=(fopen("C:\\student.txt","a"));
   if(fptr==NULL){
       printf("Error!");
       exit(1);
   }
   for(i=0;i<n;++i)
   {
      printf("For student%d\nEnter name: ",i+1);
      scanf("%s",name);
      printf("Enter marks: ");
      scanf("%d",&marks);
      fprintf(fptr,"\nName: %s \nMarks=%d \n",name,marks);
   }
   fclose(fptr);
   return 0;
}

Write a C program to write all the members of an array of strcures to a file using fwrite(). Read the array from the file and display on the screen.

#include <stdio.h>
struct s
{
char name[50];
int height;
};
int main(){
    struct s a[5],b[5];   
    FILE *fptr;
    int i;
    fptr=fopen("file.txt","wb");
    for(i=0;i<5;++i)
    {
        fflush(stdin);
        printf("Enter name: ");
        gets(a[i].name);
        printf("Enter height: "); 
        scanf("%d",&a[i].height); 
    }
    fwrite(a,sizeof(a),1,fptr);
    fclose(fptr);
    fptr=fopen("file.txt","rb");
    fread(b,sizeof(b),1,fptr);
    for(i=0;i<5;++i)
    {
        printf("Name: %s\nHeight: %d",b[i].name,b[i].height);
    }
    fclose(fptr);
}