Confused about declaration, definition
This question already has an answer here:
int a; is both a declaration (the variable can be used) and a definition (it has its own memory) but if it is an automatic variable, it is not initialized.
extern int a; is a mere declaration and is not a definition.
From here:
Most of the time, when you declare a variable, you are also providing the definition. What does it mean to define a variable, exactly? It means you are telling the compiler where to create the storage for that variable. For example, if you write:
int x;
int main()
{
x = 3;
}
The line int x; both declares and defines the variable; it effectively says, "create a variable named x, of type int. Also, the storage for the variable is that it is a global variable defined in the object file associated with this source file
this is a part from site more relevant to your question please refer to the link for further your misconception will be hopefully cleared http://www.cprogramming.com/declare_vs_define.html
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