program:
#include<stdio.h>
void area(float Lenght,float breadth)
{
float a=Lenght*breadth;
printf("Area of rectangle=%f",a);
}
int main()
{
float l,b;
printf("Enter Lenght=");
scanf("%f",&l);
printf("Enter breadth=");
scanf("%f",&b);
area(l,b);
}
output: