Stack implementation in C language.

Given below is a simple stack implementation in C language. Three main functions of a stack are implemented here, namely push, pop and top.

	#include <stdio.h>
	#include <stdlib.h>
	int top;
	int push( int temp , int *arr)
	{
	if(top >10 )
	{
	printf("stack is full\n");
	return -1;
	}
	if(arr == NULL)
	{
	printf("stack is empty\n");
	top = 1;
	arr[0] = temp;
	return 1;
	}
	else
	{
	top = top + 1;
	arr[top] = temp;
	return 1;
	}
	}
	int pop(int *arr)
	{
	int temp = 0;
	if(arr == NULL)
	{
	printf("stack doesnt exist\n");
	return -1;
	}
	if(top == 0)
	{
	printf("stack is empty\n");
	return -1;
	}
	else if (top > 0)
	{
	temp = arr[top];
	top = top - 1;
	return temp;
	}
	else
	{
	printf("Invalid top value\n");
	return -1;
	}
	}
	int topstack(int *arr)
	{
	if(arr == NULL)
	{
	printf("stack doesnt exist\n");
	return -1;
	}
	if(top >= 0)
	{
	return arr[top];
	}
	else
	{
	printf("Invalid top value\n");
	return -1;
	}
	}
	int main()
	{
	int *arr;
	int popvalue;
	top = 0;
	arr = (int *) malloc (sizeof(10));
	push(1,arr);
	push(2,arr);
	push(3,arr);
	push(4,arr);
	push(5,arr);
	push(6,arr);
	push(7,arr);
	push(8,arr);
	push(9,arr);
	push(10,arr);
	push(11,arr);
	push(12,arr);
	printf("Popped value %d \n",pop(arr) );
	printf("Popped value %d \n",pop(arr) );
	printf("Popped value %d \n",pop(arr) );
	printf("Top value %d \n",topstack(arr));
	getchar();
	return 0;
	}

view raw stack.c hosted with ❤ by GitHub