C++ std::is_compound模板用法及代码示例

C++ STL的std::is_compound模板用于检查类型是否为复合类型。它返回一个显示相同的布尔值。

用法：

template < class T > struct is_compound;

参数：此模板包含单个参数T(特质类)，以检查T是否为复合类型。

返回值：此模板返回一个布尔值，如下所示：

True：如果类型是复合类型。
False：如果类型是非复合类型。

以下示例程序旨在说明C++ STL中的is_compound模板：

程序1:：

// C++ program to illustrate 
// is_compound template 
  
#include <iostream> 
#include <type_traits> 
using namespace std; 
  
// main program 
struct GFG1 { 
}; 
  
union GFG2 { 
    int var1; 
    float var2; 
}; 
  
int main() 
{ 
    cout << boolalpha; 
    cout << "is_compound:"
         << endl; 
    cout << "GFG1:"
         << is_compound<GFG1>::value 
         << endl; 
    cout << "GFG2:"
         << is_compound<GFG2>::value 
         << endl; 
    cout << "int:"
         << is_compound<int>::value 
         << endl; 
    cout << "int*:"
         << is_compound<int*>::value 
         << endl; 
    return 0; 
}

输出：

is_compound:
GFG1:true
GFG2:true
int:false
int*:true

程序2:：

// C++ program to illustrate 
// is_compound template 
  
#include <iostream> 
#include <type_traits> 
using namespace std; 
  
class GFG1 { 
}; 
  
enum class GFG2 { var1, 
               var2, 
               var3, 
               var4 
}; 
  
// main program 
int main() 
{ 
    cout << boolalpha; 
    cout << "is_compound:"
         << endl; 
    cout << "GFG1:"
         << is_compound<GFG1>::value 
         << endl; 
    cout << "GFG2:"
         << is_compound<GFG2>::value 
         << endl; 
    cout << "int[10]:"
         << is_compound<int[10]>::value 
         << endl; 
    cout << "int &:"
         << is_compound<int&>::value 
         << endl; 
    cout << "char:"
         << is_compound<char>::value 
         << endl; 
  
    return 0; 
}

输出：

is_compound:
GFG1:true
GFG2:true
int[10]:true
int &:true
char:false

程序3:：

// C++ program to illustrate 
// is_compound template 
  
#include <iostream> 
#include <type_traits> 
using namespace std; 
  
// driver code 
int main() 
{ 
    class gfg { 
    }; 
  
    cout << boolalpha; 
    cout << "is_compound:"
         << endl; 
    cout << "int(gfg::*):"
         << is_compound<int(gfg::*)>::value 
         << endl; 
    cout << "float:"
         << is_compound<float>::value 
         << endl; 
    cout << "double:"
         << is_compound<double>::value 
         << endl; 
    cout << "int(int):"
         << is_compound<int(int)>::value 
         << endl; 
  
    return 0; 
}

输出：

is_compound:
int(gfg::*):true
float:false
double:false
int(int):true

相关用法

注：本文由纯净天空筛选整理自rajasethupathi大神的英文原创作品 std::is_compound Template in C++。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。