Java-encapsulate three triangular trapezoid circles and test the three types of objects with one program execution entry

Public class diliuzhou_1 {/*** @ Param ARGs */public static void main (string [] ARGs) {// todo auto-generated method stub} class trangle {double sidea, sideb, sidec, area, length; Boolean boo; Public trangle (double A, double B, double C) {sidea = A; // parameter A, B, C is assigned to sidea, sideb, sidec sideb = B; sidec = C; if (a + B> C & A + C> B & B + C>) // condition expression {boo = true for A, B, and C triangle; // assign a value to boo.} Else {boo = false; // assign a value to boo.} Double getlength () {length = sidea + sideb + sidec; // method body. The value of length must be calculated and return length;} public double getarea () {If (BOO) {Double P = (sidea + sideb + sidec)/2.0; Area = math. SQRT (p * (p-sidea) * (p-sideb) * (p-sidec); return area;} else {system. out. println ("not a triangle, cannot calculate area"); Return 0 ;}} public void setabc (double A, double B, double C) {sidea = A; sideb = B; sidec = C; // parameters A, B, and C are assigned to sidea, sideb, and side respectively. C If (a + B> C & A + C> B & B + C> A) // A, B, and C constitute the conditional expression of the triangle {boo = true; // assign a value to boo.} Else {boo = false; // assign a value to boo. }}} Class lader {double above, bottom, height, area; lader (double A, double B, double H) {above = A; // method body, set parameter, B and C are assigned to the values above, bottom, and height Bottom = B; Height = H;} double getarea () {area = (above + bottom) * Height/2.0f; // method body, which requires that return area;} class circle {double radius, area, length; Circle (double r) {radius = R; // method body} double getarea () {area = 3.14 * radius; // method body, which requires that return area;} double getlength () {length = 6.28 * radius; // code of the getarea method body. Return length is required to be calculated.} void setradius (double newradius) {radius = newradius;} double getradius () {return radius ;}}

Create a program entry

 

Public class main {public static void main (string ARGs []) {double length, area; circle = NULL; trangle; lader; trangle TT = new trangle (2, 5, 8); lader LL = new lader (3, 5, 8); Circle cc = new circle (3); // create an object circle length = cc. getlength (); // call the method to return the perimeter and assign it to length system. out. println ("circle perimeter:" + length); Area = cc. getarea (); // call the Circle Method to return the area and assign it to area system. out. println ("Area of the circle:" + Area); Length = TT. getlength (); // call the trangle method to return the perimeter and assign it to length system. out. println ("Triangle perimeter:" + length); Area = TT. getarea (); // call the trangle method to return the area and assign it to area system. out. println ("Triangle Area:" + area); Area = ll. getarea (); // lader calls the method to return the area and assigns it to area system. out. println ("Trapezoid area:" + area); TT. setabc (, 1); // set three edges in the trangle call method. You must change the three edges to, 34, and 1. Area = TT. getarea (); // call the trangle method to return the area and assign it to area system. out. println ("Area of the modified triangle:" + area); length = TT. getlength (); // call the trangle method to return the perimeter and assign it to length system. out. println ("the perimeter of the modified triangle:" + length );}}