User input and output with double in C

[Qomplainerz]

Example:

double radius;
printf("Enter the radius of a circle: ");
scanf("%lf", &radius);
double area = 3.14159265359 * radius * radius;
printf("The area of the circle is: %.2lf\n", area);

Explanation:

In this example, we declare a double variable radius to store the user's input.
We prompt the user to enter the radius of a circle using printf().
We use the %lf format specifier in scanf() to read a double-precision value from the user and store it in the radius variable.
We calculate the area of the circle using the formula area = π * r^2, where π is approximated as 3.14159265359.
Finally, we print the calculated area using printf(). The .2 in the format specifier %.2lf ensures that the area is displayed with two decimal places.