Q.Write a C program to accept the radius of a circle and compute the area and its perimeter. The textbook presents this worked program, transcribed exactly as printed (including its printed errors):

#include<stdio.h>  
void main()  
{  
float radius, perimeter, PI=3.142, Area;  
printf("Enter the radius\n");  
scanf("%f", &radius);  
area=PI*radius*radius;  
pmeter=2.0*PI*radius;  
printf("Area of the circle=%5.2f\n", area);  
printf("Perimeter=%5.2f\n", pmeter);  
}  

Sample output printed in the textbook:

Enter the radius  
2.4  
Area of the circle = 18.09  
Perimeter = 15.08  

Arithmetic operators carry out the basic mathematical operations in C. There are five of them:

• + addition, - subtraction, * multiplication, / division, and
• % the modulus (remainder) operator, which gives the remainder of an integer division.

An arithmetic expression is formed by joining variables and constants with these operators, for example y = 3*x*x + 4*x - 2;, which is the C form of $y = 3x^2 + 4x - 2$. Note that C has no power symbol, so $x^2$ is written as x*x, and multiplication must be written explicitly with *.

Two rules matter when evaluating arithmetic:

1. Integer division truncates. When both operands are integers, / discards the fractional part, so 25/6 gives 4, not 4.166. To get a real result, at least one operand must be real (e.g. sum/4.0). …