stack,c

// C program for array implementation of stack 
#include <limits.h> 
#include <stdio.h> 
#include <stdlib.h> 
  
// A structure to represent a stack 
struct Stack { 
    int top; 
    unsigned capacity; 
    int* array; 
}; 
  
// function to create a stack of given capacity. It initializes size of 
// stack as 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; 
} 
  
// Stack is full when top is equal to the last index 
int isFull(struct Stack* stack) 
{ 
    return stack->top == stack->capacity - 1; 
} 
  
// Stack is empty when top is equal to -1 
int isEmpty(struct Stack* stack) 
{ 
    return stack->top == -1; 
} 
  
// Function to add an item to stack.  It increases top by 1 
void push(struct Stack* stack, int item) 
{ 
    if (isFull(stack)) 
        return; 
    stack->array[++stack->top] = item; 
    printf("%d pushed 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]; 
} 
  
// Driver program to test above functions 
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; 
}