在C++中，如何使用文件指针读入文件？

A.

#include

FILE *file = fopen("example.txt", "r");

B.

#include

FILE *file = freopen("example.txt", "r");

C.

#include

FILE *file = fopen("example.txt", "w");

D.

#include

FILE *file = freopen("example.txt", "w");