Q. Define a method for keeping two stacks within a single linear array S in such a way that neither stack overflows until entire array is used and a whole stack is never shifted to a different location within the array. Write down the routines for pushing and poping elements in two the stacks.          

Ans.

/* The Two Stacks Into One Array */

#include

#define MAX 50

int mainarray[MAX];

int top1=-1,top2=MAX;

void push1(int elm)

{

if((top2-top1)==1)

{

clrscr();

printf("\n Array has been Filled !!!");

return;

}

mainarray[++top1]=elm;

}

void push2(int elm)

{

if((top2-top1)==1)

{

clrscr();

printf("\n Array has been Filled !!!");

return;

}

mainarray[--top2]=elm;

}

int pop1()

{

int temp;

if(top1<0)

{

clrscr();

printf(" \n This Stack Is Empty !!!");

return -1;

}

temp=mainarray[top1];

top1--;

return temp;

}

int pop2()

{

int temp;

if(top2>MAX-1)

{

clrscr();

printf(" \n This Stack Is Empty !!!");

return -1;

}

temp=mainarray[top2];

top2++;

return temp;

}