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Can we initialize the variables globally?

Because I am getting error like this:
main.c:6:3: error: initializer element is not constant

What I have tried:

C++
#include <stdio.h>
#include<stdlib.h>
struct Node{
    int a;
    int b;
}*a;
a=(struct Node*)malloc(sizeof(struct Node));
int main()
{
    printf("Hello world");
    return 0;
}
Posted
Updated 22-Jul-21 2:48am

It's not inside a function, which means it has to be an initializer - which is assigned only when the item is declared - which means it must be a constant value at compile time, which malloc cannot be.

Move the line inside the main function and it'll work:
C
#include <stdio.h>
#include<stdlib.h>
struct Node{
    int a;
    int b;
}*a;
int main()
{
    a=(struct Node*)malloc(sizeof(struct Node));
    printf("Hello world");
    return 0;
}
   
No, you cannot do that (calling a function outside other functions).
Typically you do
C
#include <stdio.h>
#include<stdlib.h>
struct Node
{
    int a;
    int b;
} * a = NULL;

int main()
{
  if ( ! a)
    a=(struct Node*)malloc(sizeof(struct Node));

  printf("Hello world");

  if (a)
    free(a);

  return 0;
}
   

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