math - Java confusion initializing variables within different cases -
my source code below attempting create program calculate area diameter , circumference of circle when user enters a,c, or d. want return correct response depending on user input. managed 3 return within first case earlier separating them proved difficult ideas?
import java.util.scanner; public class test { public static void main(string[] args) { scanner sc = new scanner(system.in); system.out.print("this program determine area, circumference or diameter circle. type area c circumference , d diameter"); // prompt user input of capitol character while (!sc.hasnext("[a-z]+")) { system.out.println(sc.next().charat(0) + " not capital letter! non alphanumeric values not permitted."); // error response unnaceptable character a-z specified range of acceptable characters } char c = ' '; c = sc.next().charat(0); // looking through user input @ character @ position 0 switch (c) { case 'a': system.out.print("enter radius: "); //i storing entered radius in floating point float radius = sc.nextfloat(); float area = ((float) math.pi) * ((float)(radius * radius)); system.out.printf("the area of circle is: %.2f \n", area); break; case 'c': system.out.print("enter radius: "); //i storing entered radius in floating point float circumference = ((float)(math.pi * 2 * radius)); system.out.printf("the circumference of circle is: %.2f \n", circumference); break; case 'd': system.out.print("enter radius: "); //i storing entered radius in floating point float diameter = ((float)(radius * 2)); system.out.printf("the diameter of circle is: %.2f \n", diameter); break; } } }
you define , calculate float radius = sc.nextfloat(); inside case 'a': radius used in 2 other cases. in switch 1 case executed (when there no fall though), therefor, when select case 'c' or 'd' radius variable never defined , you'll error.
to solve this, define , calculate radius outside switch
... float radius = sc.nextfloat(); switch (c) { case 'a': system.out.print("enter radius: "); //i storing entered radius in floating point float area = ((float) math.pi) * ((float)(radius * radius)); system.out.printf("the area of circle is: %.2f \n", area); break; case 'c': system.out.print("enter radius: "); //i storing entered radius in floating point float circumference = ((float)(math.pi * 2 * radius)); system.out.printf("the circumference of circle is: %.2f \n", circumference); break; case 'd': system.out.print("enter radius: "); //i storing entered radius in floating point float diameter = ((float)(radius * 2)); system.out.printf("the diameter of circle is: %.2f \n", diameter); break; } ...
Comments
Post a Comment