Default parameter learning for functions in C + +

　　　　The default parameter refers to the automatic use of a default value when an argument is omitted from a function call.

For a function with a parameter list, you must add a default value from right to left (that is, her right side must have a default value first)

Fun (int, int,1,int,int), etc. It's clear enough!!

1 Char* Left (Const Char* STR,intn=1);2 intMain ()3 {4 }5 6 Char* Left (Const Char* STR,intn =1)//Error7 {8}

1 declaration with default parameters, no default value when implemented (OK)

2 implemented with default parameters, no default value declared (OK)

1 Char* Left (Const Char* STR,intn=1);2 intMain ()3 {4 }5 6 Char* Left (Const Char* STR,intN)7 {8 9}

1 Char* Left (Const Char* STR,intn);2 intMain ()3 {4 5 }6 Char* Left (Const Char* STR,intn =1)7 {8 9}

Use default parameters to override function overloading:

If a set of overloaded functions (which may have default parameters) allows the same number of calls , the two semantics of the call will be raised.

1 voidFuncint);//one of the overloaded functions2 voidFuncint，int=4);//two of the overloaded functions with default parameters3 voidFuncint=3，int=4);//three of the overloaded functions with default parameters4 5Func7);//error: Which of the 3 overloaded functions is called?6Func -, -)//error: Which one of the following 2 overloaded functions is called?

Careful,!!!!!!!!!!!!!.

Default parameter learning for functions in C + +