Area of a Circle

                              Area of a Circle

The program must accept the diameter of the circle as a command line argument and print the area of the circle rounding it up to 2 decimal places.

Example Input/Output 1:
Input:
14

Output:
154.00

Example Input/Output 2:
Input:
14.42

Output:
163.38

Example Input/Output 3:
Input:
1

Output:
0.79

Code:

#include<stdio.h>

#include<stdlib.h>

int main(int argc, char *argv[])

{

    double r=atof(argv[1])/2;

    printf("%.2f",3.142857*r*r);

}

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