std::is_compound Template in C++
Last Updated :
19 Nov, 2018
The std::is_compound template of C++ STL is used to check the whether the type is a compound type or not. It returns a boolean value showing the same.
Syntax:
template < class T > struct is_compound;
Parameter: This template contains single parameter T (Trait class) to check whether T is a compound type or not.
Return Value: This template returns a boolean value as shown below:
- True: if the type is a compound type.
- False: if the type is a non-compound type.
Below programs illustrate the is_compound template in C++ STL:
Program 1:
#include <iostream>
#include <type_traits>
using namespace std;
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;
}
|
Output:
is_compound:
GFG1: true
GFG2: true
int: false
int*: true
Program 2:
#include <iostream>
#include <type_traits>
using namespace std;
class GFG1 {
};
enum class GFG2 { var1,
var2,
var3,
var4
};
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;
}
|
Output:
is_compound:
GFG1: true
GFG2: true
int[10]: true
int &: true
char: false
Program 3:
#include <iostream>
#include <type_traits>
using namespace std;
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;
}
|
Output:
is_compound:
int(gfg::*): true
float: false
double: false
int(int): true
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