- While passing arguments, the function creates copies of the arguments passed to it. This type of passing arguments is called passing by value.
- We can pass structure as arguments.
- We can also return a structure. Useful while returning multiple values.
- Passing by reference :
- e.g. void intfunc(float& a, int& b);
- We can also pass structures by reference.
- References don’t exist in c.
- Types of Recursion :
- Inline functions : Use ‘inline’ keyword in function declaration or declarator.
- inline keyword is actually a request to compiler. Sometimes compiler will ignore the request and compile the function as a normal function.
- inline functions are similar to #define in C. But inline functions provide better type checking and do not need special care with parenthesis.
- Scope and Storage class : The scope of variable determines which parts of program can access it and it storage class determines how long it stays in existence.
- Types of scope : Local (in current block) and file scope (through out a file).
- Storage classes : Automatic (lifetime of function in which defined) and static (lifetime of program).
- Variables inside a function called local variables or automatic variables.
- Automatic name is used because variables are created automatically when function is called and destroyed when function returns.
- Non initialized local variables will have garbage value.
- Non initialized global variables will have 0 value.
- Static variable :
- Scope of local variable
- Lifetime of global variable.
- Local variable and function arguments are stored in stack and global and static variables are stored on heap.
- Return by reference :
- int& func();
- Can call it : func() = 15; — It gives value of 15 to variable returned by function func.
- We can’t do two things :
- Can’t return constant.
- Cannot return local variable reference.
- ‘const’ function argument : To protect the modification of variable passed by reference.
- e.g. void func(const int& a);