6-cia/rc/geo2d-bb.cc

 class Line
exams/2020-12-03/bb
 some solutions

6-cia/src/geo2d-bb.cc

@@ -24,8 +24,20 @@ class Point
   double yc;  //y-coordinate
 };
 
-//                                         implementation
+//-------------------------------------------------- Line
+//                                            declaration
+class Line
+{
+ public:
+  Line(const Point& p0,const Point& p1);
+  ~Line();
+ private:
+  Point p;  //by value
+  Point q;  //by value
+};
 
+//------------------------------------------------- Point
+//                                         implementation
 Point::Point(double x,double y)
 :xc(x),yc(y)  //init list
               //xc=x;yc=y
@@ -61,23 +73,31 @@ double Point::distance(const Point& other) const
                    other.yc - yc);
 } 
 
+//-------------------------------------------------- Line
+//                                         implementation
+Line::Line(const Point& p0,const Point& p1)
+:p(p0)  //p by value copy constructor
+,q(p1)  //q by value copy constructor
+{
+ std::cout<<"constructor Line\n";
+}
 
-
-/*
-no copy constructor
-constructor Point 5,7
-constructor Point 8,11 
-d=5
-destructor Point 8,11
-destructor Point 5,7
-*/
+Line::~Line()
+{
+ std::cout<<"destructor Line\n";
+}
 
 //---------------------------  use case
 int main(int argc,char** args)
 {
- Point p(5, 7);
- Point q(8,11);
- auto d=p.distance(q);  //other = c++ reference to q
- std::cout<<"d="<<d<<"\n"; 
+ Point p(5, 7);  //instance birth p constructor Point 5,7
+ Point q(8,11);  //instance birth q constructor Point 8,11
+ Line l(p,q);    //copy constructor Point 5,7
+                 //copy constructor Point 8,11
+		 //constructor Line
  return 0;
-}
+}                //death  l destructor Line
+                 //death     l.q destructor Point 8,11 
+		 //death     l.p destructor Point 5,7
+		 //death  q destructor Point 8,11
+		 //death  p destructor Point 5,7

6-cia/src/svg-demo.svg

@@ -4,11 +4,11 @@
 <svg xmlns="http://www.w3.org/2000/svg"
      xmlns:xlink="http://www.w3.org/1999/xlink">
 <!-- see  http://www.w3.org/TR/SVG11/ -->
+<circle cx="100" cy="100" r="50" fill="white" stroke-width="5" stroke="green"/>
 <line x1="0" y1="0" x2="150" y2="100" 
       stroke-width="20" stroke="yellow"></line>
 <line x1="150" y1="100" x2="300" y2="400" 
       stroke-width="5" stroke="red"></line>
       
-<circle cx="100" cy="100" r="50" stroke="green"/>
-<rect x="100" y="200" width="200" height="50"/>
+<rect x="100" y="200" width="200" height="50" fill="white" stroke="blue"/>
 </svg>

exams/2020-12-03/bb/cos-sin.cc → exams/2020-12-03/bb/src/cos-sin.cc

@@ -15,7 +15,36 @@ static unsigned PI=(1<<31);
 
 static const SCALE SC=
 {
-use program cos-sin-table.cc to generate the table
+/*  0 */  5.41196100146197012215e-01,
+/*  1 */  5.09795579104159179984e-01,
+/*  2 */  5.02419286188155678197e-01,
+/*  3 */  5.00602998235196383625e-01,
+/*  4 */  5.00150636020651018221e-01,
+/*  5 */  5.00037651915547720627e-01,
+/*  6 */  5.00009412535887820539e-01,
+/*  7 */  5.00002353106286046014e-01,
+/*  8 */  5.00000588274841284431e-01,
+/*  9 */  5.00000147068602074363e-01,
+/* 10 */  5.00000036767143773986e-01,
+/* 11 */  5.00000009191785554918e-01,
+/* 12 */  5.00000002297946388730e-01,
+/* 13 */  5.00000000574486569427e-01,
+/* 14 */  5.00000000143621670112e-01,
+/* 15 */  5.00000000035905389772e-01,
+/* 16 */  5.00000000008976375199e-01,
+/* 17 */  5.00000000002244093800e-01,
+/* 18 */  5.00000000000561106717e-01,
+/* 19 */  5.00000000000140332190e-01,
+/* 20 */  5.00000000000035083048e-01,
+/* 21 */  5.00000000000008770762e-01,
+/* 22 */  5.00000000000002220446e-01,
+/* 23 */  5.00000000000000555112e-01,
+/* 24 */  5.00000000000000222045e-01,
+/* 25 */  5.00000000000000111022e-01,
+/* 26 */  5.00000000000000000000e-01,
+/* 27 */  5.00000000000000000000e-01,
+/* 28 */  5.00000000000000000000e-01,
+/* 29 */  5.00000000000000000000e-01,
 };
 
 void cos_sin8(unsigned alfa,double* c,double* s) //0<=alfa<pi/4
@@ -54,7 +83,34 @@ void cos_sin8(unsigned alfa,double* c,double* s) //0<=alfa<pi/4
 
 
 //cos_sin{
-//your code
+void cos_sin(unsigned alfa,double* c,double* s)
+{
+ if (alfa<PI/4)
+    {
+     cos_sin8(alfa,c,s);
+     return;
+    }
+ //PI/4<=alfa<2*PI
+ if (alfa<PI/2)
+   {
+    auto a=PI/2-alfa; //0<=a<PI/4
+    cos_sin8(a,s,c);
+    return;
+   }
+ //PI/2<=alfa<2*PI
+ if (alfa<PI)
+    {
+     auto a=alfa-PI/2; //0<=a<PI/2
+     cos_sin(a,s,c);
+     *c=-*c;
+     return;
+    }
+ //PI<=alfa<2*PI
+ auto a=alfa-PI; //0<=a<PI
+ cos_sin(a,c,s);
+ *c=-*c;
+ *s=-*s;
+}
 //cos_sin}
 
 //****** DO NOT CHANGE BELOW THIS LINE