设有以下类的定义： class Ex { int x; public: void setx(int t=0); }; 若在类外定义成员函数setx( )，以下定义形式中正确的是
A．void setx(int {…}
B．void Ex::setx(int {…}
C．Ex::void setx(int {…}
D．void Ex::setx( ){…}
参考答案：B
解析： 选项A可以排除，原因是类的成员函数的定义必须用域作用符::进行限定；选项C的限定位置不对，函数的类型应在最前面。根据上下文可以指导，setx为单参成员函数，在定义时也必须指定参数，因此选项D也可以排除，正确答案为B。
| Some people associate migration mainly with birds. Birds do travel vast distances, but mammals also migrate. An example is the caribou, reindeer that graze on the grassy slopes of northern Canada. When the weather turns cold, they travel south until spring. Their tracks are so well-worn that they are clearly visible from the air. Another migrating mammal is the Alaska fur seal. These seals breed only in the Pribilot Islands in the Bering Sea. The young are born in June and by September are p enough to go with their mothers on a journey of over 3,000 miles. Together they swim down the Pacific Coast of North America. The females and young travel as far as southern California. The males do not journey so far. They swim only to the Gulf of Alaska. In the spring, males and females all return to the islands, and there the cycle begins again. Whales are among the greatest migrators of all. The humpback and blue whales migrate thousands of miles each year from the polar seas to the tropics. Whales eat huge quantities of plankton. These are most abundant in cold polar waters. In winter, the whales move to warm waters to breed and give birth to their young. |
Which of the following is NOT true
A．Whales breed in winter.
B．Young whales are given birth in cold waters.
C．Alaska fur seals give birth to the young only in one area.
D．Alaska fur seals are born in warm weather.