C + + Fundamentals interview Selection 100 series (21-30) [C + + Basics]

"This article links"

Http://www.cnblogs.com/hellogiser/p/100-interview-questions-of-cplusplus-basics-21-30.html

"topic 21"

Run the following code to output the results?

Code

C + + Code

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/* version:1.0 Author:hellogiser Blog:http://www.cnblogs.com/hellogiser Date:2014/9/22 */ #include "StdAfx.h" #include<iostream> using namespacestd; classA { Public: Virtual voidFun (intNumber =Ten) { Std::cout <<"A::fun with Number"<< number << Endl; } }; classB: PublicA { Public: Virtual voidFun (intNumber = -) { Std::cout <<"B::fun with Number"<< number << Endl; } }; intMain () { b b; A &a = b; A.fun (); return 0; //virtual function Dynamic binding: B, the default argument is determined at compile time ... is 10 } /* B::fun with Number 10 */

Analysis

Virtual functions are dynamically bound, but the default arguments are determined at compile time, so the result is b::fun with Number 10

"topic 22"

Indicate what is wrong with the following program and correct it.

Code

C + + Code

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#include<iostream> using namespaceStd classA { Public: A (); ~a (); inti =0; //ERROR     Static intj =0; //ERROR     Const intk =0; //ERROR     Const Static Char*p ="Hello World"; //ERROR     Static voidFun (); }; A::a () { } A::~a () { } Static voidFun ()ERROR { }

"Correct code"

C + + Code

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/* version:1.0 Author:hellogiser Blog:http://www.cnblogs.com/hellogiser Date:2014/9/22 */ #include "StdAfx.h" #include<iostream> using namespacestd; classA { Public: A (); ~a (); inti;//Error     Static intJ;//Error     Const intK; //Error     Const Static Char*p;//Error     Static voidFun (); }; inta::j =0; Const Char*a::p ="Hello World"; A::a (): I (0), K (0) { } A::~a () { } voidA::fun () { } intMain () { return 0; }

"topic 23"

C + + Fundamentals interview Selection 100 series (21-30) [C + + Basics]