// C Program for Implmentation of stack (array) using structure
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
// A structure to represent a stack
struct Stack {
int top;
int maxSize;
int* array;
};
struct Stack* create(int max)
{
struct Stack* stack = (struct Stack*)malloc(sizeof(struct Stack));
stack->maxSize = max;
stack->top = -1;
stack->array = (int*)malloc(stack->maxSize * sizeof(int));
//here above memory for array is being created
// size would be 10*4 = 40
return stack;
}
// Checking with this function is stack is full or not
// Will return true is stack is full else false
//Stack is full when top is equal to the last index
int isFull(struct Stack* stack)
{
if(stack->top == stack->maxSize - 1){
printf("Will not be able to push maxSize reached\n");
}
// Since array starts from 0, and maxSize starts from 1
return stack->top == stack->maxSize - 1;
}
// By definition the Stack is empty when top is equal to -1
// Will return true if top is -1
int isEmpty(struct Stack* stack)
{
return stack->top == -1;
}
// Push function here, inserts value in stack and increments stack top by 1
void push(struct Stack* stack, int item)
{
if (isFull(stack))
return;
stack->array[++stack->top] = item;
printf("We have pushed %d to stack\n", item);
}
// Function to remove an item from stack. It decreases top by 1
int pop(struct Stack* stack)
{
if (isEmpty(stack))
return INT_MIN;
return stack->array[stack->top--];
}
// Function to return the top from stack without removing it
int peek(struct Stack* stack)
{
if (isEmpty(stack))
return INT_MIN;
return stack->array[stack->top];
}
int main()
{
struct Stack* stack = create(10);
push(stack, 5);
push(stack, 10);
push(stack, 15);
int flag=1;
while(flag)
{
if(!isEmpty(stack))
printf("We have popped %d from stack\n", pop(stack));
else
printf("Can't Pop stack must be empty\n");
flag=0;
}
return 0;
}
Output :
We have pushed 5 to stack
We have pushed 10 to stack
We have pushed 15 to stack
We have popped 15 from the stack
Do you want to Pop again? Yes: 1 No: 0
0
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