我很难理解以下模板定义和模板专业化定义是如何工作的?对我来说,factorial<34>
还是factorial<T-1>
看起来怪怪的!
例如:
factorial<T - 1>::value
意味着什么?
#include <iostream>
template<int T>
struct factorial {
enum { value = factorial<T - 1>::value * T };
};
template<>
struct factorial<1> {
enum { value = 1 };
};
int main()
{
std::cout << factorial<34>::value << std::endl;
}
g++ -o testSTL01 testSTL01.cpp -Wall
testSTL01.cpp: In instantiation of ‘factorial<13>’:
testSTL01.cpp:5:3: instantiated from ‘factorial<14>’
testSTL01.cpp:5:3: instantiated from ‘factorial<15>’
testSTL01.cpp:5:3: instantiated from ‘factorial<16>’
testSTL01.cpp:5:3: instantiated from ‘factorial<17>’
testSTL01.cpp:5:3: instantiated from ‘factorial<18>’
testSTL01.cpp:5:3: [ skipping 11 instantiation contexts ]
testSTL01.cpp:5:3: instantiated from ‘factorial<30>’
testSTL01.cpp:5:3: instantiated from ‘factorial<31>’
testSTL01.cpp:5:3: instantiated from ‘factorial<32>’
testSTL01.cpp:5:3: instantiated from ‘factorial<33>’
testSTL01.cpp:5:3: instantiated from ‘factorial<34>’
testSTL01.cpp:15:29: instantiated from here
testSTL01.cpp:5:3: warning: integer overflow in expression
start to run the app ...
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