#include "pch.h"
#include <iostream>

typedef struct Stack
{
	int* values;
	unsigned size;
    int top_index;


} stack;

void init_stack(stack* stack, unsigned size);
void free_stack(stack* stack);

void push(stack* stack, int value);//Adds an item in the stack. If the stack is full, then it is said to be an Overflow condition.
int peek(stack* stack);//Returns top element of stack.
int pop(stack* stack);//Removes an item from the stack.
int is_full(stack* stack);
int isEmpty(stack* stack);

void print_stack(stack* stack);
void print_info(stack* stack);
char get_pair(char br);

int brackets(char* str);

int main()
{
	stack stack;

	init_stack(&stack, 5);
	//print_stack(&stack);
	push(&stack, 3);
	push(&stack, 4);
	push(&stack, 3);
	push(&stack, 2);
	push(&stack, 7);

	print_stack(&stack);
	//printf("\n%d",peek(&stack));
	printf("%d", stack.top_index);
	pop(&stack);
	printf("\n");
	print_stack(&stack);
	printf("%d", stack.top_index);
	free_stack(&stack);
	char str[50] = "(a+b)(  *c*c[d-e]";
	int res = brackets(str);
	if (res == -1)
	{
		printf("Correct\n");
	}
	else
	{
		printf("error in position %d", res);
	}













	return 0;
}


void init_stack(stack* stack, unsigned size)
{

	stack->values = (int*)malloc(sizeof(int)*size);
	stack->top_index = -1;
	stack->size = size;
	return;
}
int is_full(stack* stack)// Stack is full when top is equal to the last index
{
	return stack->top_index == stack->size-1;
}
int isEmpty(stack* stack)
{
	return stack->top_index == -1;
}
void free_stack(stack* stack)
{
	free(stack->values);

	return;
}

void push(stack* stack, int value)
{
	if (is_full(stack))
		return;
	stack->values[++stack->top_index] = value;

}
int peek(stack* stack)
{
	return stack->values[stack->top_index];
}
int pop(stack* stack)
{

	if (isEmpty(stack))
		return -1;

	int item =stack->values[stack->top_index];
	(stack->top_index) -= 1; //	top = top - 1
	return item;

}

void print_stack(stack* stack)
{
	for (int i = 0; i < stack->top_index; i++)
	{
		printf("%3d", stack->values[i]);
	}

}
void print_info(stack* stack)
{




}

char get_pair(char br)
{
	switch (br)
	{
	case'(':return')';
	case'[':return']';

	case'{':return'}';

	case'<':return'>';
	}
}

int brackets(char* str)
{
	stack st;
	init_stack(&st, strlen(str));
	int i = 0;
	while (str[i])
	{
		switch (str[i])
		{
		case'(':
		case'[':
		case'{':
		case'<':
			push(&st, str[i]);
			break;
		case')':
		case']':
		case'}':
		case'>':
			if (isEmpty(&st))
			{
				return i;
			}
			if (str[i] != get_pair(pop(&st)))
			{
				return i;
			}
		default:break;
		}
		i++;

	}
	if (!isEmpty(&st))
	{
		return i;
	}
	return -1;
}