Way 2 Freshers

#include<stdio.h>
#include<conio.h>
struct stack
{
int no;
struct stack *next;
}
*start=NULL;
typedef struct stack st;
void push();
int pop();
void display();
void main()
{
char ch;
int choice,item;
do
{
clrscr();
printf("\n 1: push");
printf("\n 2: pop");
printf("\n 3: display");
printf("\n Enter your choice");
scanf("%d",&choice);
switch (choice)
{
case 1: push();
break;
case 2: item=pop();
printf("The delete element in %d",item);
break;
case 3: display();
break;
default : printf("\n Wrong choice");
};
printf("\n do you want to continue(Y/N)");
fflush(stdin);
scanf("%c",&ch);
}
while (ch=='Y'||ch=='y');
}
void push()
{
st *node;
node=(st *)malloc(sizeof(st));
printf("\n Enter the number to be insert");
scanf("%d",&node->no);
node->next=start;
start=node;
}
int pop()
{
st *temp;
temp=start;
if(start==NULL)
{
printf("stack is already empty");
getch();
exit();
}
else
{
start=start->next;
free(temp);
}
return(temp->no);
}
void display()
{
st *temp;
temp=start;
while(temp->next!=NULL)
{
printf("\nno=%d",temp->no);
temp=temp->next;
}
printf("\nno=%d",temp->no);
}

#include<stdio.h>
#include<conio.h>
int i,len,pos,num;
void main()
{
int a[100];
void insert(int a[], int, int, int);
clrscr();
printf("Enter integers to be read");
scanf("%d",&len);
printf("Enter integers");
    for(i=0;i<=len;i++)
      {
	scanf("%d",&a[i]);
      }
printf("Enter integer to be inserted");
scanf("%d",&num);
printf("Enter position in the array for insertion");
scanf("%d",&pos);
--pos;
insert(a,len,pos,num);
}
void insert (int a[], int len, int pos, int num)
{
    for(i=len;i>=pos;i--)
      {
	a[i+1]=a[i];
      }
	a[pos]=num;
	  if(pos>len)
	    {
		printf("insertion outside the array");
	    }
	len++;
	printf("New array");
for(i=0;i<len;i++)
{
printf("%d\n",a[i]);
}
getch();
}

#include<stdio.h>
#include<conio.h>
int i,len,pos,num;
void main()
{
int a[100];
void insert(int a[], int, int, int);
clrscr();
printf("Enter integers to be read");
scanf("%d",&len);
printf("Enter integers");
    for(i=0;i<=len;i++)
      {
	scanf("%d",&a[i]);
      }
printf("Enter integer to be inserted");
scanf("%d",&num);
printf("Enter position in the array for insertion");
scanf("%d",&pos);
--pos;
insert(a,len,pos,num);
}
void insert (int a[], int len, int pos, int num)
{
    for(i=len;i>=pos;i--)
      {
	a[i+1]=a[i];
      }
	a[pos]=num;
	  if(pos>len)
	    {
		printf("insertion outside the array");
	    }
	len++;
	printf("New array");
for(i=0;i<len;i++)
{
printf("%d\n",a[i]);
}
getch();
}