C ++期望的主表达式错误 [英] C++ expected primary-expression error

问题描述

在使用g ++编译下面的代码时，我得到了一个'int''之前的主表达式错误。你知道为什么和如何解决它吗？谢谢！

I got a 'expected primary-expression before 'int'' error when compiling with g++ the following code. Do you know why and how to fix it ? Thank you !

 struct A
 {
     template <typename T>
     T bar() { T t; return t;}
 };

 struct B : A
 {
 };

 template <typename T>
 void foo(T  & t)
 {
     t.bar<int>();
 }

 int main()
 {
     B b;
     foo(b);
 }

推荐答案

$ c> foo（）函数，编译器不知道bar是成员模板。您必须告诉它：

When compiling the foo() function, the compiler doesn't know that bar is a member template. You have to tell it that:

template <typename T>
void foo(T & t)
{
  t. template bar<int>(); // I hope I put template in the right position
}

编译器认为bar只是一个成员变量，你试图比较它与某些东西，例如 t.bar< 10 。因此，它会抱怨int不是一个表达式。

The compiler thinks that bar is just a member variable, and that you try to compare it with something, e.g. t.bar < 10. As a result, it complains that "int" is not an expression.

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