Square and Cube in MACROS

#include<iostream.h>
#include<conio.h>

#define SQUARE(X)    (X * X)
#define CUBE(X)          (X * X * X)

float circle(float);

void main()
{
    int no, k, m;
    clrscr();

    cout<<"Enter a number: ";
    cin>>no;

    k = SQUARE(no);
    m = CUBE(no);

    cout<<"Square is : "<<k;
    cout<<"Cube is : "<<m;
}