Macro Expansions

Macro Expansions


A macro consist of a define directive, a template and a macro expansion.

Eg: #define TOWN “Borella”
#define MAX 212
#define AND &&

During preprocessing the C preprocessor replaces the every occurrence of TOWN in the program
with “Borella”

e.g.
 // Alphabetic character count
#include<stdio.h>
#include<conio.h>
#define isalpha(c) ((c>=’a’ && c<=’z’ ) || (c >=’A’ && c <= ‘Z’))
void main()
{
int ch, nc=0;
puts(“Enter a word or a sentence:”)
while (ch = getchar() != ‘\n’)
if (isalpha(ch)) nc++;
printf(“Your word or sentence contains %d alphabetic characters \n”, nc);
}