C++ Functions Revisited INFSY 307 C++

Must always consider three parts of the Program: Function Prototype: Can be in the header or top of a function (including main) 2.Function Call: May be in ANY function (main ( ) or any other) 3.Function Header: Indicates the top of the function.

C++ Functions n Function Prototype void get_number (); n Function Call m.get_number (); n Function void math::get_number () Note: 1) format of each! 2) typing and argument consistency!

C++ Function – given a return value n Function Prototype int get_number (); n Function Call int x; x=m.get_number (); n Function int math::get_number () { int num; num=read_char_to_int (); return num; }

C++ Functions n Function name – Name must correspond to name in prototype n Function type must correspond to type in prototype n Local variables only available during function execution/global variables do not lose value int math::get_number () { int num; num=read_char_toint (); return num; }

C++ Functions CONSIDERATIONS! n Provide function PRE and POST condition comments under EACH the prototype Others must know what is the beginning state of associated variables, what the function does, and what to expect as complete after execution.

Function Arguments: 1.Are contained in each critical component: a)Function call b)Function prototype c)Function Heading 2.Must match as far as: a)type b)order

C++ Sample Function with argument list and a return value void samp::output (double value, int years, char name []) { cout <<setw (20)<<“ “<< “Name is: “<<name<<endl; cout<<setw (20)<<“ “<<“Years in Program: “years<<endl; cout<<setw (20)<<“ “<<“GPA: “<<value<<endl; return; } int main () samp s; char name []; int yrs; double gpa; s.output (gpa, yrs, name); //assume are defined.