C++选择题积累03.docxVIP

001下面关于数组的描述错误的是：正确答案: C D ??你的答案: C?(错误)在C++语言中数组的名字就是指向该数组第一个元素的指针长度为n的数组，下标的范围是0－n-1数组的大小必须在编译是确定数组只能通过值参数和引用参数两种方式传递给函数解析A，错误，原因：如果数组是一维数组，A正确。但如果是多维数组则A错误。B. ? 说法不够严谨，在这里默认数组长度n0。C?，错误?，C99中提到了variable length arrays的概念，允许在编译时不指定数组大小，而在运行时才确定D，错误，数组只能传值吧，指针也算传值+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++002关于内联函数正确的是（）正确答案: B ??你的答案: B?(正确)类的私有成员函数不能作为内联函数在所有类说明中内部定义的成员函数都是内联函数类的保护成员函数不能作为内联函数使用内联函数的地方会在运行阶段用内联函数体替换掉解析+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++003有以下程序1234567main( ){?? int sum,pad,pAd;? sum = pad =?5;? pAd = + + sum,pAd + +,+ + pad;? printf(%d\n,pad);?}程序的输出结果是6解析C语言区分大小写,pad与pAd是两个不同的变量。首先将5赋值给两个变量,由于赋值运算符的优先级高于逗号运算符,所以计算pAd = + + sum,此时pAd为6,sum也为6,然后计算pAd + +,pAd的值变为7,+ + pad,pad的值变为6,所以选择B。+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++004下列 C 代码中，不属于未定义行为的有：______。正确答案: C ??你的答案: C?(正确)int i=0;i=(i++);char *p=”hello”;p[1]=’E’char *p=”hello”;char ch=*p++int i=0;printf(“%d%d\n”,i++ i--)解析+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++005有如下程序段：12char ch=-1;printf(“%02x,%02x”,ch,(unsigned?char)ch);则输出：ffffffff,ff解析输出格式%x，接受的参数是无符号整数，第二个参数ch字符型转化变成32为无符号int型，输出为ffffffff.%x是把变量作为十六进制整数来写。+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++006以下程序输出结果是_ B-1___。class A{public:????virtual void func(int val = 1)????{ std::coutA-val std::endl;}????virtual void test()????{ func();}};class B :?public A{public:????void func(int val=0){std::coutB-val std::endl;}};int main(int argc ,char* argv[]){????B*p =?new B;????p-test();return 0;}解析p-test();在调用时，子类中没有这个函数，会继续返回父类中。即使父类中的函数是virtual。+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++007关于struct和class，下列说法正确的是（）正确答案: A C ??你的答案: A C?(正确)struct的成员默认是public，class的成员默认是privatestruct不能继承，class可以继承struct可以有无参构造函数str