c中的默认模板参数

假设我有一个功能模板StrCompare @H_801_5@ @H_801_5@

template<typename T=NonCaseSenCompare>//NonCaseSenCompare is a user defined class look at the detailed code below.
int StrCompare(char* str1,char* str2)
{
...
}

@H_801_5@现在在主要功能我写了一行

@H_801_5@

char* str1="Zia";
char* str2="zia";
int result=StrCompare(str1,str2);

@H_801_5@它应该工作,因为我们提供了一个默认的模板参数,但它没有编译器给出以下错误
没有匹配函数来调用`StrCompare(char *&,char *&)’
现在详细的代码由.给出

@H_801_5@

#include<iostream.h>
class CaseSenCompare
{
public: 
static int isEqual(char x,char y)
{
return x==y;
}
};
class NonCaseSenCompare
{
public:
static int isEqual(char x,char y)
{
char char1=toupper(X);
char char2=toupper(y);
return char1==char2;
}
};
template<typename T=NonCaseSenCompare>
int StrCompare(char* str1,char* str2)
{
for(int i=0;i < strlen(str1)&& strlen(str2);i++)
{
if(!T::isEqual(str1[i],str2[i]))
return str1[i]-str2[i];
}
return strlen(str1)-strlen(str2);
}

main()
{
char* ptr1="Zia ur Rahman";
char* ptr2="zia ur Rahman";
int result=StrCompare(ptr1,ptr2);//compiler gives error on this line
cout<<result<<endl;
system("pause");
}

@H_801_5@如果我写

@H_801_5@

int result=StrCompare<>(ptr1,ptr2);

@H_801_5@编译器提供相同的错误消息.

template<typename Comp>
int StrCompare(char* str1,char* str2,Comp = NonCaseSenCompare())
{
  ...
}

StrCompare("abc","aBc",CaseSenCompare());

StrCompare("abc","aBc"); // uses NonCaseSenCompare

struct CaseSenCompare {
  bool operator()(char x,char y) const {return x==y;}
};