remove conio.h

I wanted to do that but I need a C equivalent of clrscr()
Otherwise, the output looks bad :'(delete all those global variables
I've seen that, in my compiler, if i declare a variable globally, the problem of garbage values disappears. If only there was a constructor in C, this problem would have never risen :sad:a few comments would be nice to explain what those functions do
I thought the names were enough ... but okay, I'll give the comments but will you improve my grades? :P

I'll edit the code later but i will ...

Okay, this is a temporary fix. Love it or leave it :p

#include <stdio.h>
#include <alloc.h>
#include <conio.h>

typedef struct student
{
	int roll;
	int age;
	struct student *link;
}std;

void append(int,int);			//	Creating the database for the 1st time
void display(void);				//	Displays the entire database
void search(int);              	//	Searches for a particular roll number
void delRoll(int);              //	Deletes an entry according to the given roll number
void addAtBegin(int,int);   	//	Inserts an entry in the begining
void addAtLoc(int,int,int);    	//	Inserts an entry at the given location
void addAftRoll(int,int,int);   //	Inserts an entry after a specified roll number
void noOfStudents(void);		//  Finds the total number of students

std *head;	std *temp;	std *temp2;	std *add;

int main()
{
	int n;	int r;	int a;	int pos;	int fRoll;

	do
	{
		clrscr();
		printf("\n\t================");
		printf("\n\tSTUDENT DATABASE");
		printf("\n\t================\n");
		printf("\n\t1 - Apending Information About A Student");
		printf("\n\t2 - Displaying Information Of All Students");
		printf("\n\t3 - Searching Information About A Student");
		printf("\n\t4 - Deleting Information About A Student According To Roll No");
		printf("\n\t5 - Adding Information About A Student At Begining");
		printf("\n\t6 - Adding Information About A Student At Any Location");
		printf("\n\t7 - Adding Information About A Student After A Roll Number");
		printf("\n\t8 - Finds Total Number Of Students");
		printf("\n\t9 - Exit");
		printf("\n\n\tChoice : ");
		fflush(stdin);
		scanf("%d",&n);
		switch(n)
		{
			case 1 :
				clrscr();
				printf("\n\n\tEnter Roll Number : ");
				scanf("%d",&r);
				printf("\n\n\tEnter Age : ");
				scanf("%d",&a);
				append(r,a);
				getch();
				break;
			case 2 :
				clrscr();
				printf("\n\n\tInformation List\n\n");
				display();
				getch();
				break;
			case 3 :
				clrscr();
				printf("\n\n\tEnter The Roll Number You Want To Search : ");
				scanf("%d",&r);
				search(r);
				getch();
				break;
			case 4 :
				clrscr();
				printf("\n\n\tEnter The Roll Number You Want To Delete : ");
				scanf("%d",&r);
				delRoll(r);
				getch();
				break;
			case 5 :
				clrscr();
				printf("\n\n\tEnter Roll Number : ");
				scanf("%d",&r);
				printf("\n\n\tEnter Age : ");
				scanf("%d",&a);
				addAtBegin(r,a);
				getch();
				break;
			case 6 :
				clrscr();
				printf("\n\n\tEnter Location : ");
				scanf("%d",&pos);
				printf("\n\n\tEnter Roll Number : ");
				scanf("%d",&r);
				printf("\n\n\tEnter Age : ");
				scanf("%d",&a);
				addAtLoc(pos,r,a);
				getch();
				break;
			case 7 :
				clrscr();
				printf("\n\n\tEnter Roll Number After Which New Data Will Be Put : ");
				scanf("%d",&fRoll);
				printf("\n\n\tEnter Roll Number : ");
				scanf("%d",&r);
				printf("\n\n\tEnter Age : ");
				scanf("%d",&a);
				addAftRoll(fRoll,r,a);
				getch();
				break;
			case 8 :
				clrscr();
				noOfStudents();
				getch();
				break;
			case 9 :
				printf("\n\n\tThank You!");
				getch();
				break;
			default :
				printf("\n\n\tThe Specified Option Does Not Exist!");
				getch();
				break;
		}
	}while(n!=9);
	return 0;
}

void append(int r,int a)
{
	temp2 = (std *)malloc(sizeof(std));
	temp2 -> roll = r;
	temp2 -> age = a;

	temp = head;

	if(temp == NULL)
	{
		head = temp2;
		head -> link = NULL;
	}
	else
	{
		while(temp -> link != NULL)
		{
			temp = temp -> link;
		}
		temp -> link = temp2;
		temp2 -> link = NULL;
	}
}

void display(void)
{
	temp = head;
	if(temp == NULL)
	{
		printf("\n\n\tEmpty Database!");
		return;
	}

	while(temp != NULL)
	{
		printf("\tRoll No. : %d\tAge : %d\n", temp -> roll, temp -> age);
		temp = temp -> link;
	}
}

void search(int r)
{
	temp = head;
	while(temp != NULL)
	{
		if(temp -> roll == r)
		{
			printf("\n\tRoll Number Exists!\n");
			printf("\tRoll No. : %d\tAge : %d\n", temp -> roll, temp -> age);
			return;
		}
		temp = temp -> link;
	}
	printf("\n\n\tSpecified Roll Number Does Not Exist!");
}

void addAtBegin(int r,int a)
{
	temp2 = (std *)malloc(sizeof(std));
	temp2 -> roll = r;
	temp2 -> age = a;
	temp2 -> link = head;
	head = temp2;
}

void delRoll(int r)
{
	if(head == NULL)
	{
		printf("\n\n\tEmpty Database!");
		return;
	}
	temp = head -> link;
	temp2 = head;

	if(temp2 -> roll == r)
	{
		head = temp;
		free(temp2);
		return;
	}

	while(temp -> roll != r)
	{
		temp = temp -> link;
		temp2 = temp2 -> link;
        if(temp == NULL)
		{
			printf("\n\tRoll Number Does Not Exist");
			return;
		}
	}

	temp = temp -> link;
	free(temp2 -> link);
	temp2 -> link = temp;
}

void addAtLoc(int pos,int r,int a)
{
	int i;
	add = (std *)malloc(sizeof(std));
	add -> roll = r;
	add -> age = a;

	if(pos == 1)
	{
		add -> link = head;
		head = add;
		return;
	}

	temp = head;
	for(i = 0;i < pos - 2;i++)
	{
		temp = temp -> link;
		if(temp == NULL)
		{
			printf("\n\tLocation Does Not Exist");
			return;
		}
	}

	temp2 = temp -> link;
	temp -> link = add;
	add -> link = temp2;
}

void addAftRoll(int fRoll,int r,int a)
{
	temp = head;
	while(temp -> roll != fRoll)
	{
		temp = temp -> link;
		if(temp == NULL)
		{
			printf("\n\tRoll Number Does Not Exist");
			return;
		}
	}

	temp2 = temp -> link;

	add = (std *)malloc(sizeof(std));
	add -> roll = r;
	add -> age = a;

	temp -> link = add;
	add -> link = temp2;
}

void noOfStudents(void)
{
	int l = 0;
	temp = head;
	while(temp!=NULL)
	{
		temp = temp -> link;
		l++;
	}
	printf("\n\n\tTotal Number Of Students : %d", l);
}

It looks some issue in deleting the entry..

Fixed