Step 1: Start
Step 2: define PI 3.14
Step 3: Declare variables R, A, and C
Step 4: Read the value of Radius R
Step 5: Calculate the area of a circle
        A = PI * R * R 
Step 6: Print the area of a circle
Step 7: Calculate the circumference of a circle
        C = 2 * PI * R
Step 8: Print the circumference of a circle
Step 9: End

#include <stdio.h>
#define PI 3.14
int main()
{
    float R, A, C;
    printf("———————————————————————————————————————————");
    printf("\nProgram to calculate the area and circumference of a circle");
    printf("\n———————————————————————————————————————————");
    printf("\nEnter the radius of a circle ");
    scanf("%f", &R);
    A = PI * R * R;
    printf("\nThe area of a circle is %f ", A);

    C = 2 * PI * R;
    printf("\n\nThe circumference of a circle is %f ", C);
    printf("\n———————————————————————————————————————————\n");
    return 0;
}

kodingwindow@kw:~$ gcc kw.c
kodingwindow@kw:~$ ./a.out
———————————————————————————————————————————
Program to calculate the area and circumference of a circle
———————————————————————————————————————————
Enter the radius of a circle 10

The area of a circle is 314.000000 

The circumference of a circle is 62.799999 
———————————————————————————————————————————
kodingwindow@kw:~$