Operations on a Stack

// C Program for Implmentation of stack (array) using structure
#include<stdio.h>
#include<stdlib.h>
#include<limits.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