struct test{
int a=1111111;
}test;
vincentdeMacBook-Air:datasturte vincent$ g++ struct.cpp -o structpp struct.cpp:4:6: warning: in-class initialization of non-static data member is a C++11 extension [-Wc++11-extensions] int a=11111111; ^ 1 warning generated.
struct test{
const int a=1111111;
}test;
vincentdeMacBook-Air:datasturte vincent$ g++ struct.cpp -o structpp struct.cpp:4:12: warning: in-class initialization of non-static data member is a C++11 extension [-Wc++11-extensions] const int a=11111111; ^ struct.cpp:29:4: error: cannot assign to non-static data member 'a' with const-qualified type 'const int' q.a=10; ~~~^ struct.cpp:4:11: note: non-static data member 'a' declared const here const int a=11111111; ~~~~~~~~~~^~~~~~~~~~ 1 warning and 1 error generated. vincentdeMacBook-Air:datasturte vincent$ g++ struct.cpp -o structpp struct.cpp:29:4: error: cannot assign to static data member 'a' with const-qualified type 'const int' q.a=10; ~~~^
struct test{
static int a=11111111;
}test;
struct.cpp:4:18: note: static data member 'a' declared const here static const int a=11111111; ~~~~~~~~~~~~~~~~~^~~~~~~~~~ 1 error generated.
vincentdeMacBook-Air:datasturte vincent$ g++ struct.cpp -o structpp struct.cpp:4:12: error: non-const static data member must be initialized out of line static int a=11111111; ^ ~~~~~~~~ 1 error generated.
同样问题:http://stackoverflow.com/questions/13662441/c11-allows-in-class-initialization-of-non-static-and-non-const-members-what-c