Macros with substitution type

1. C
Preprocessors
Macro
Simple
Parameterized
By Asst. Prof. Sonali Gholve- Doifode

2. Preprocessor
C
Source code
Preprocessor Compiler
• Preprocessor is a collection of special statements,
called directives, that are executed at the beginning
of the compilation process.
• #
• Eg. #include => include the header file into
the program.
• #include<stdio.h>, #include<string.h>

3. Macro
• What is macro?
• Macro is a small part of a code that is given a
name. Whenever the name is used, it is
replaced by the contents of the macro.
• you can define macro in C using #define
preprocessor directive
• Simple macro substitution
• Parameterized macro/function like macro

4. Simple macro substitution
• It is used to simple replacement of identifier by string.
• Eg. To calculate area of circle using macro
#include<stdio.h>
#define PI 3.14
int main()
{
float rad, area;
printf(“ Enter the radius”);
scanf(“%f”,&rad);
area=PI *rad*rad;
printf(“Area of circle=%f”, area);
return 0;
}

5. Parameterized macro/Function like
macro substitution
• Macro that takes the parameter.
• Eg. To calculate square of number using macro
#include<stdio.h>
#define square (x) ((x)*x)
int main()
{
int p;
p=square(5);
printf(“n Square of 5 is=%d”, p);
return 0;
}