Explain macro substitution directive in c programming language?

Answer:

e.g.

 

#define pie 3.14

void main()

{

float r=3,area;

area=3*r*pie;

printf(“%f”,area);

getch();

}

 

Before the starting of actual compilation an intermediate is formed which is:

 

We can see only in place of pie, 3.14 has pasted.

If is very long or we want to write in next line, end first line by \.

e.g.

 

#define word c is powerful \

language.