无法找到区域设置感知版本的StrSafe函数（StringCbPrintf_lW）(Locale-aware version of StrSafe function (StringCbPrintf_lW) cannot be found)

 
 
 没有任何地方宣布这一点，我认为这是搞砸我的原因。 
 
 
 等等，它在那里声明 - 在方法的标题中： 
 
static double GetDouble(string prompt)
//                      ^^^^^^^^^^^^^ This is the declaration of prompt
 
 prompt与您看到的其他变量不同，它不是正常变量：它是方法的形式参数 。 
 
 与使用赋值运算符=初始化和明确赋值的常规变量不同，通过调用方法隐式赋值形式参数。 当您调用该方法时，您将向其传递一个带有实际参数的表达式，该参数用作该表达式到形式参数的赋值。 想象一下，在第一次调用之前，将prompt变量分配为"Enter the base: " ，然后在第二次调用之前为其指定"enter the exponent: "以了解调用GetDouble 。 

 
 
Nowhere is this declared and I think that's what's messing me up.
 
 
Wait, it's declared right there - in the header of the method:
 
static double GetDouble(string prompt)
//                      ^^^^^^^^^^^^^ This is the declaration of prompt
 
prompt is different from other variables that you have seen in that it is not a normal variable: it is a formal parameter of a method.
 
Unlike regular variables which you initialize and assign explicitly with the assignment operator =, formal parameters are assigned implicitly by virtue of calling a method. When you call the method, you pass it an expression with the actual parameter, which acts as an assignment of that expression to the formal parameter. Imagine that the prompt variable is assigned "Enter the base: " before the first call, and then it is assigned "enter the exponent: " before the second call to understand what is going on when you call GetDouble.