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How to declare a variable in C++?
In C++, declaration and definition are often confused. A declaration means (in C) that you are telling the compiler about type, size and in case of function declaration, type and size of its parameters of any variable, or user-defined type or function in your program. No space is reserved in memory for any variable in case of a declaration.
The Definition on the other hand means that in additions to all the things that declaration does, space is additionally reserved in memory. You can say "DEFINITION = DECLARATION + SPACE RESERVATION".
Following are examples of declarations −
extern int a; // Declaring a variable a without defining it
struct _tagExample { int a; int b; }; // Declaring a struct
int myFunc (int a, int b); // Declaring a functionWhile following are examples of definition −
int a;
int b = 0;
int myFunc (int a, int b) { return a + b; }
struct _tagExample example;
Updated on: 11-Feb-2020
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