Assigning a value to structure element out side main

Question

I created a structure with two elements and tried to assign a value to one of the structure elements outside main function. But I'm getting error while compiling.

#include <stdio.h>
#include <stdlib.h>
struct node{
    char a;
    int b;
};
struct node sr;
sr.b = 48;
int main(){
    printf("Value:%d",sr.b);
    return 0;
}

I'm assigning value after the declaration. Why is this code giving error.

error message

error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘.’ token

Answer 1

You cannot have a statement which needs runtime execution outside main(), i.e., in file scope. It needs to be present inside some block scope, inside a function so as to determine when to be executed.

You can however, use initialization to have the initial values stored for the members of the structure type variable. Something like

 struct node sr = {'Z', 1};

will initialize sr.a to 'Z' and sr.b to 1. In case you're only interested in initializing member b, you'll be needing designated initializers, like

struct node sr = { .b = 1 };

Answer 2

Put the following lines inside main() function.

struct node sr;
sr.b = 48;

Why? You cannot have a statement which needs runtime execution outside main(). It needs to be in the scope of a block, for example, inside a function so as to determine when to be executed.