第八章单元测试
- 静态成员函数不必通过该类的对象调用,可以直接用类名以及作用域运算符::进行调用。 ( )
- 关于类的静态成员的不正确描述是 ( )
- 若有以下说明,则对n的正确访问语句是( )
class Y{
public:
static int n;
};
intY::n;
Y objY; - const表示常量,类的const数据成员初始化只能在成员初始化列表里。( )
const int *p说明不能修改( )
- The lifetime of a static member variable is same as ___( )
- #include <stdio.h>
class Test{
static int x;
public:
Test() { x++; }
static int getX() {return x;}
};
int Test::x = 0;
void main(){
printf("%d ", Test::getX());
Test t[5];
printf("%d ", Test::getX());
}
Output? ( ) - #include <stdio.h>
class Player{
private:
int id;
static int next_id;
public:
int getID() { return id; }
Player() { id = next_id++; }
};
int Player::next_id = 1;
void main(){
Player p1;
Player p2;
Player p3;
printf("%d ", p1.getID());
printf("%d ", p2.getID());
printf("%d ", p3.getID());
}
Output? ( ) - #include <stdio.h>
int main(){
const int x;
x = 10;
printf("%d", x);
return 0;
}
Output? ( ) - #include <stdio.h>
class Point{
int x, y;
public:
Point(int i = 10, int j = 10){
x = i;
y = j;
}
int getX() const {
return x;
}
int getY() {
return y;
}
};
void main(){
const Point t;
printf("%d %d", t.getX(), t.getY());
}
Output? ( )
A:对 B:错
答案:对
A:静态成员函数不拥有this指针,需要通过类参数访问对象成员 B:静态数据成员要在类外定义和初始化 C:静态成员不属于对象,是类的共享成员 D:只有静态成员函数可以操作静态数据成员
A:Y::n=1; B:n=1; C:objY::n=1; D:Y->n
A:错 B:对
A:p指针指向的变量; B:p指针; C:p指针指向的数据类型;
A:The private of variable of any object B:Lifetime of the program C:The public variable of any object D:The first object of its class
A:5 5 B:0 5 C:0 0 D:5 0
A:1 2 3 B:1 1 1 C:1 3 1 D:2 2 2
A:Error B:10 C:Garbage value
A:0 0 B:Compile error C:10 10
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