Ahmed Ahmed - 3 months ago 6
C Question

Stack implementation placing codes in multiple files

i am trying to implement a stack by writing all its functions in a separate source file.but i get a lot of errors saying incompatible pointer type.these errors don't show up when i include the functions in the main C file.these are my files.i am new to this.help me correct them.
thank you.
my main code is

#include "myfunctions.h"
int main()
{
int operation,data;
struct stack *One = (struct stack *)malloc(sizeof(struct stack));
One->top = -1;
printf("stack functionality \n");
while(1)
{
if (isEmpty(One))
{
printf("enter 1 to push \n");
scanf("%d",&operation);
}
else if (isFull(One))
{
printf("stack is full.enter 2 to pop or 3 to diplay \n");
scanf("%d",&operation);
}
else
{
printf("enter 1 to push,2 to pop,3 to display 4 to exit \n");
scanf("%d",&operation);
}
switch (operation)
{
case 1: printf("enter data to be pushed \n");
scanf("%d",&data);
push(One,data);
break;
case 2: printf("%d \n",pop(One));
break;
case 3: display(One);
break;
case 4:exit(0);
}
}
}


stackfns code

#include <myfunctions.h>
bool isEmpty(struct stack *b)
{
if(b->top == -1) return true;
else return false;
}
bool isFull(struct stack *b)
{
if(b->top == 9) return true;
else return false;
}
void push(struct stack *b,int data)
{
b->a[++(b->top)] = data;
}
int pop(struct stack *b)
{
return (b->a[(b->top)--]);
}
void display(struct stack *b)
{
int i;
for (i=0;i<10;i++)
printf("%d ",b->a[i]);
printf("\n");
}


header file

#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
extern bool isEmpty(struct stack *b);
extern bool isFull(struct stack *b);
extern void push(struct stack *b,int data);
extern int pop(struct stack *b);
extern void display(struct stack *b);
#define max_size 10
struct stack
{
int a[max_size];
int top;
};

Answer

In the header file you need to first decalre the struct:

#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>

#define max_size 10
struct stack
{
    int a[max_size];
    int top;
};

extern bool isEmpty(struct stack *b);
extern bool isFull(struct stack *b);
extern void push(struct stack *b,int data);
extern int pop(struct stack *b);
extern void display(struct stack *b);

In addition, there is no need to expose the internal implementation of the data structure. You can do something like:

.h file:

typedef struct xx_t xx_t;

.c file:

struct xx_t {
    ...
};