Example of C Language Creating Stack Array

// Example : create a stack in  C language
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
 
// Create a structure to represent the stack
struct Stack {
    int top;
    unsigned capacity;
    int* array;
};
 
// Create a stack for a given capacity. It initializes the size of the stack to 0
// 
struct Stack* createStack(unsigned capacity)
{
    struct Stack* stack = (struct Stack*)malloc(sizeof(struct Stack));
    stack->capacity = capacity;
    stack->top = -1;
    stack->array = (int*)malloc(stack->capacity * sizeof(int));
    return stack;
}
 
// When top equals the last index, the stack is full
int isFull(struct Stack* stack)
{
    return stack->top == stack->capacity - 1;
}
 
// Check if the stack is empty
int isEmpty(struct Stack* stack)
{
    return stack->top == -1;
}
 
// Add an element to the stack (push in stack)
void push(struct Stack* stack, int item)
{
    if (isFull(stack))
        return;
    stack->array[++stack->top] = item;
    printf("%d pushed to stack\n", item);
}
 
// Pop and return an element at the top of the stack  
int pop(struct Stack* stack)
{
    if (isEmpty(stack))
        return INT_MIN;
    return stack->array[stack->top--];
}
 
// Returns the top element in the stack, but does not pop the element
int peek(struct Stack* stack)
{
    if (isEmpty(stack))
        return INT_MIN;
    return stack->array[stack->top];
}
 
// test
int main()
{
    struct Stack* stack = createStack(100);
 
    push(stack, 10);
    push(stack, 20);
    push(stack, 30);
 
    printf("%d popped from stack\n", pop(stack));
 
    return 0;
}