Given a list of names of students in a class, write a program to store the names in a file on disk. Make a provision to display the nth name in the list (n is data to be read) and to display all names starting with S.

Students.txt

Siraj
Karan
Rahul
Deepak
Varun
Priya
Nazia
Gulabsa
Farheen
Farzana
Rizwan
Sonam

#include<stdio.h>
#include<conio.h>
#include<string.h>
#include<stdlib.h>
#include<Windows.h>

void add_info(char*, char*);
void display(char*);
void disbys(int, char*);

int main()
{
	disbys(1, "Students.txt");
	_getch();
	return 0;
}

void add_info(char *name, char *file)
{
	FILE *fp;
	fp = fopen(file, "r+");
	if (fp == NULL)
		fp = fopen(file, "w");
	fseek(fp, 0, SEEK_END);
	fputs(name, fp);
	putc('\n', fp);
	fclose(fp);
}

void display(char *file)
{
	FILE *fp;
	char name[30];
	fp = fopen(file, "r");
	if (fp == NULL)
	{
		printf("File do not exist.");
		_getch();
		exit(1);
	}
	while (fscanf(fp, "%s", name) != -1)
		puts(name);
	fclose(fp);
}

void disbys(int num, char *file)
{
	FILE *fp;
	int i;
	char name[30];
	fp = fopen(file, "r");
	if (fp == NULL)
	{
		printf("File do not exist.");
		_getch();
		exit(2);
	}

	for (i = 1; fscanf(fp, "%s", name) != -1; i++)
	{
		if (i == num)
		{
			switch (num)
			{
			case 1:
				printf("%dst name is : ", num);
				break;
			case 2:
				printf("%dnd case is : ", num); 
				break;
			case 3:
				printf("%drd name is : ", num); 
				break;
			default:
				printf("%dth name is : ", num);
			}
			printf("%s\n\n", name);
			break;
		}
	}
	if (fscanf(fp, "%s", name) == -1)
		printf("There's only %d names.\n", i);

	rewind(fp);
	while (fscanf(fp, "%s", name) != -1)
		if (name[0] == 'S' || name[0] == 's')
			puts(name);
	fclose(fp);
}