C: Changing value in Union resulting in error?

Question

typedef union
{
    int integer;
    char* string;
} Value;

main()
{
  Value v = { 1 };
  v = { 2 }; // getting the error on this 
}

Answer 1

Curly braces used at the time of initialization only. Once the initialized section got over, union or structure variables members are accessed by using "dot" operator.

Answer 2

You should access a union member using a dot operator. Eg. - v.integer=0; v.string=NULL;

This works fine in the first line because it is an initialization.

Value v= { 1 } ;

Infact it is called partial initialization where if you initialize just one or more members, the rest are treated to be assigned as 0. Curly braces work only in case of initialization.