ERROR when using malloc() and sizeof() function - c

Question

Following is a program I made in C for implementation of stack using array and pointers:
#include<stdio.h>
#include<stdlib.h>
struct ArrayStack {
int top;
int capacity;
int *array;
};
struct ArrayStack *createStack(int cap) {
struct ArrayStack *stack;
stack = malloc(sizeof(struct Arraystack));
stack->capacity = cap;
stack->top = -1;
stack->array(malloc(sizeof(int) * stack->capacity));
return stack;
}
int isFull(struct ArrayStack *stack) {
if(stack->top == stack->capacity-1)
return 1;
else
return 0;
}
int isEmpty(struct ArrayStack *stack) {
if(stack->top == -1)
return 1;
else
return 0;
}
void push(struct ArrayStack *stack, int item) {
if(!isFull(stack)) {
stack->top++;
stack->array[stack->top] = item;
} else {
printf("No more memory available!");
}
}
void pop(struct ArrayStack *stack) {
int item;
if(!isEmpty(stack)) {
item = stack->array[stack->top];
stack->top--;
} else {
printf("Memory is already empty!");
}
}
int main() {
struct ArrayStack *stack;
stack = createStack(10);
int choise;
int item;
while(1) {
system("clear");
printf("\n1. Push");
printf("\n2. Pop");
printf("\n3. Exit");
printf("\n\n\n\t\tPlease choose your option!");
scanf("%d",&choise);
switch(choise) {
case 1:
printf("\nEnter a number");
scanf("%d",&item);
push(stack,item);
break;
case 2:
pop(stack);
break;
case 3:
exit(0);
break;
default :
printf("\nPlease enter a valid choise!");
break;
}
}
}
The following error is coming whenever I try to compile this code using gcc compiler:
prog.c:10:25: error: invalid application of 'sizeof' to incomplete type 'struct Arraystack'
stack = malloc(sizeof(struct Arraystack));
^
prog.c:13:3: error: called object is not a function or function pointer
stack->array(malloc(sizeof(int) * stack->capacity));
^
I have used online IDEs like ideone and codechef's ide but same error is coming again. I am totally struck, this is really annoying!

Answer 1

First your errors:
stack = malloc(sizeof(struct ArrayStack));
You typed Arraystack (lower case s).
stack->array=malloc(sizeof(int) * stack->capacity);
You typed stack->array(malloc(sizeof(int) * stack->capacity)); which is syntactically a function call which is why the compiler complains about array not being a function pointer.
In addition:
Introduce a function void destroyStack(ArrayStack* stack) to free() the malloc()ed space in createStack(). Call it towards the end of main() when you've finished with the stack.
Always render unto free() what malloc() rendered unto thee.
Your pop() doesn't return the popped value.
You should probably return values indicating failure when push() and pop() fail.