I was working on pop and push methods on the stack. Actually in this code I am creating dynamic array using pointers and malloc function. Then I was trying to add or delete elements to dynamic array with pop and push methods.But I getting the error in the question. I can't see any error in the code. Can you help me?

Here my main.c file

#include <stdio.h>
#include <stdlib.h>
#include "main_header.h"
stack * init(){
    stack *s = (stack *) malloc(sizeof(stack));
    s->items = NULL;
    s->top = 0;
    s->count = 2;
    return s;
}

int pop(stack *s){
    if(s->items == NULL){
        printf("Items is empty.\n");
        return -1;
    }
    if(s->top<=s->count/4){
        int *items2 = (int *)malloc(sizeof(int)*s->count/2);
        
        for (int i = 0; i < (s->count/2); i  ){
            items2[i] = s->items[i];
        }
        free(s->items); // burada "dizi" adındaki dizimiz dizi2 ile aynı yeri gösterdiğinde önceki 2 elemanlık dizi lost in space olacak bunu önlemek için free(dizi) diyerek o 2 elemanı bellekten siliyoruz.
        s->items = items2;
        s->count /= 2;

    }
    return s->items[--s->top];
}

void push(int a, stack *s){
    if(s->items == NULL){
        s->items = (int *)malloc(sizeof(int) * 2);
    }
    if(s->top>=s->count){
        int *items2 = (int *)malloc(sizeof(int)*s->count*2);
        for (int i = 0; i < s->count; i  )
            items2[i] = s->items[i];
        free(s->items); // burada "dizi" adındaki dizimiz dizi2 ile aynı yeri gösterdiğinde önceki 2 elemanlık dizi lost in space olacak bunu önlemek için free(dizi) diyerek o 2 elemanı bellekten siliyoruz.
        s->items = items2;
        s->count *= 2;
        
    }
    s->items[s->top  ] = a;
}

void getItems(stack *s){
    printf("count: %d\n", s->count);
    for (int i = 0; i < s->top; i  ) {
        printf("%d\n", s->items[i]);
    }
}

main_header.h file

#ifndef main
#define main

struct s {
    int count;
    int top;
    int *items;
    
};
typedef struct s stack;
stack * init(void);
int pop(stack *);
void getItems(stack *);
void push(int, stack *);
#endif

test_stack.c file

#include <stdio.h>
#include <stdlib.h>
#include "main_header.h"


int main(){
    
    stack *s1 = init();
    
    stack *s2 = init();
    
    for (int i = 0; i < 10; i  ) {
        push(i*10, s1);
    }
    
    getItems(s1);
    
    for (int i = 0; i < 10; i  ) {
        push(pop(s1), s2);
    }
    
    return 0;
}

CodePudding user response：

After #define main in “main_header.h”, the code int main(){ in “test_stack.c” is replaced by int (){. This causes the syntax error that the compiler (not Xcode) reports.

Do not use main in “main_header.h” as an indicator for whether the header file has been included already. Use some other name that you will not use for anything else, such as main_h or main_header_h.

(Clang is the compiler. Xcode is the overall integrated development environment that facilitates use of the compiler, organizes your projects files, opens editors, maintains your project options, and so on.)