作业及其答案汇总作业及其答案汇总.doc

一、类和对象基本概念 1) 写出下面程序的运行结果： #include iostream.h class Apple { private : static int nTotalNumber; public: Apple() { nTotalNumber ++; } ~Apple( ) { nTotalNumber --; } static void PrintTotal() { cout nTotalNumber endl; } }; int Apple::nTotalNumber = 0; Apple Fun( const Apple a ) { a.PrintTotal(); return a ; } int main () { Apple * p = new Apple[4]; Fun( p[2]); Apple p1, p2; delete [] p; p1.PrintTotal(); } /* 4 1 */ 2) 写出下面程序的运行结果： #include iostream.h class Sample{ public: int v; Sample() { }; Sample(int n):v(n) { }; Sample( Sample x) { v = 2 + x.v ; } }; Sample PrintAndDouble( Sample o) { cout o.v; o.v = 2 * o.v; return o; } int main() { Sample a(5); Sample b = a; Sample c = PrintAndDouble( b ); cout endl; cout c.v endl; Sample d; d = a; cout d.v ; } /* 9 22 5 */ 3) 下面的程序输出结果是： 0 5 请填空补足程序。所填内容不允许包含分号。 class A { public: int val; A(____________ ){ val = n; }; ___A ________ GetObj() { return _* this_______; } }; main() { A a; cout a.val endl; a.GetObj() = 5; cout a.val endl; } /* int n =0 A * this */ 4) 下面程序的输出是： 3+4i 5+6i 请补足Complex类的成员函数。不能增加成员变量。 #include iostream #include string.h using namespace std; class Complex { private: double r,i; public: void Print() { cout r + i i endl; } }; int main() { Complex a; a = 3+4i; a.Print(); a = 5+6i; a.Print(); } /* Complex() { }; Complex( char * s) { r = s[0] - 0; i = s[2] - 0; } */ 5) 下面程序的输出是： 10 请补足Sample类的成员函数。不能增加成员变量。 #include iostream.h class Sample{ public: int v; Sample(int n):v(n) { }; }; int main() { Sample a(5); Sample b = a; cout b.v ; } /* Sample( Sample x) { v = 2 * x.v ; } */ 6)下面程序的输出是： This Hello 请补足MyString类的成员函数。不能增加成员变量。 #include iostream.h #include string.h class MyString{ char * p; public: MyString( char * s ) { p = new char[strlen(s)+1]; strcpy(p,s); } ~MyString() { delete [] p;} const char * c_str() { return p;} }; int main() { MyString s1(This), s2 =s1; s2.