c++ - 模板和字符串流的问题

Question

我想创建使用 stringstream 将字符串转换为数字的函数。如果我假设我的号码是 int:

int stringToNumber(string str)
{
    stringstream ss;
    ss << str;
    int num;
    ss >> num;
    return num;
}
cout << stringToNumber("182") + 100 << endl; //282

这段代码工作正常。但是当我尝试使用模板时出现错误。下面是我的代码:

template <typename number>
number stringToNumber(string str)
{
    stringstream ss;
    ss << str;
    number num;
    ss >> num;
    return num;
}

错误:

main.cpp: In function ‘int main()’:
main.cpp:17:33: error: no matching function for call to ‘stringToNumber(const char [4])’
     cout << stringToNumber("125") + 280 << endl;
                                 ^
main.cpp:17:33: note: candidate is:
main.cpp:6:8: note: template<class number> number stringToNumber(std::string)
 number stringToNumber(string str)
        ^
main.cpp:6:8: note:   template argument deduction/substitution failed:
main.cpp:17:33: note:   couldn't deduce template parameter ‘number’
     cout << stringToNumber("125") + 280 << endl;

Answer 1

您的模板参数不能以这种方式推导。您必须明确提供模板参数:

std::cout << stringToNumber<int>("125");