function macro
#include <iostream>
using namespace std;
#define getmax(a,b) ((a)>(b)?(a):(b))
int main()
{
int x=5, y;
y= getmax(x,2);
cout << y << endl;
cout << getmax(7,x) << endl;
return 0;
}Macro Expansion
#include <iostream>
#define CUBE(a) ( (a) * (a) * (a) )
#define THREE(a) a * a * a
int main()
{
long x = 5;
long y = CUBE(x);
long z = THREE(x);
std::cout << "y: " << y << std::endl;
std::cout << "z: " << z << std::endl;
long a = 5, b = 7;
y = CUBE(a+b);
z = THREE(a+b);
std::cout << "y: " << y << std::endl;
std::cout << "z: " << z << std::endl;
return 0;
}y: 125
z: 125
y: 1728
z: 82
standard macro names: __LINE__, __DATE__, __cplusplus
#include <iostream>
using namespace std;
int main()
{
cout << "This is the line number " << __LINE__;
cout << " of file " << __FILE__ << ".\n";
cout << "Its compilation began " << __DATE__;
cout << " at " << __TIME__ << ".\n";
cout << "The compiler gives a __cplusplus value of " << __cplusplus;
return 0;
}