k stacks
//Program in C++ to implement k stacks in an array
#include <iostream>
using namespace std;
class kstack{
int *s; //stack
int *index; //prev occupied and next available indexes of stack
int *top_of_stack; //top of every stack
int next_available; //next available index
public:
//initialize every value
kstack(int capacity,int number_of_stacks){
s = new int[capacity];
index = new int[capacity];
top_of_stack = new int[number_of_stacks];
next_available = 0;
for(int i=0;i<capacity;i++)
index[i] = (i != capacity-1)?i+1 : -1;
for(int i=0;i<number_of_stacks;i++)
top_of_stack[i] = -1;
}
void push(int,int); //push given element to given stack no.
void pop(int); //pop an element from given stack no.
};
void kstack::push(int stack_num,int value){
if(next_available == -1){
cout<<"All Stacks overflowed\n";
return;
}
int free_index = index[next_available];
//set new value
s[next_available] = value;
//set prev index for current stack's top index
index[next_available] = top_of_stack[stack_num];
//set top of stack to curr index
top_of_stack[stack_num] = next_available;
//set next next_available to next free index
next_available = free_index;
cout<<"Element pushed successfully\n";
}
void kstack::pop(int stack_num){
int top_index = top_of_stack[stack_num];
if(top_index == -1)
cout<<"Stack "<<stack_num<<" is empty!\n";
int top_element = s[top_of_stack[stack_num]];
cout<<top_element<<" poped\n";
//set top of stack to prev top of stack
top_of_stack[stack_num] = index[top_index];
//set index to point to next available index
index[top_index] = next_available;
//set next available to current poped index
next_available = top_index;
}
int main() {
//instantiate kstack
kstack s(6,3);
//push elements to respective given stack
s.push(0,2);
s.push(0,15);
s.push(2,10);
s.push(1,4);
s.pop(0);
s.push(2,3);
s.pop(2);
s.push(2,5);
s.push(2,6);
s.push(3,7);
s.push(2,8); //whole stack array is full at this point
return 0;
}