Updated exercise 0 with epsilon comparison in homework1.cpp

1 files changed, 28 insertions, 14 deletions

diff --git a/Year 1/Programming introduction/Homeworks/homework1.cpp b/Year 1/Programming introduction/Homeworks/homework1.cpp
index f443cb9..b0eed83 100644
--- a/Year 1/Programming introduction/Homeworks/homework1.cpp
+++ b/Year 1/Programming introduction/Homeworks/homework1.cpp
@@ -8,6 +8,20 @@ using namespace std;
  * Exercise 0
  */
 
+double const FLOAT_EPSILON_FLOOR = 0.0001, FLOAT_EPSILON_CEIL = FLOAT_EPSILON_FLOOR * 9;
+
+bool eq(double a, double b) {
+	return ((a - b) < 0.0 ? (b - a) : (a - b)) <= FLOAT_EPSILON_FLOOR;
+}
+
+bool lt(double a, double b) {
+	return !eq(a, b) && (a - b) < FLOAT_EPSILON_CEIL;
+}
+
+bool mt(double a, double b) {
+	return lt(b, a);
+}
+
 double distanceBetweenPoints(int x1, int y1, int x2, int y2)
 {
 	int sideA = x1 - x2, sideB = y1 - y2;
@@ -24,41 +38,41 @@ void ex0() {
 	double x, y;
 	cin >> x >> y;
 
-	if (x == 0) // if it's on the Y ordinate
+	if (eq(x, 0)) // if it's on the Y ordinate
 		cout << "On a line" << endl;
-	else if (distanceBetweenPoints(0, 0, x, y) < 4.0) {
-		float pointSlope = y / x;
+	else if (lt(distanceBetweenPoints(0, 0, x, y), 4.0)) {
+		double pointSlope = y / x;
 
-		if (x == -2.828 || x == 2.828 || pointSlope == SLOPE_B || pointSlope == SLOPE_C || pointSlope == SLOPE_D || pointSlope == SLOPE_E)
+		if (eq(x, -2.828) || eq(x, 2.828) || eq(pointSlope, SLOPE_B) || eq(pointSlope, SLOPE_C) || eq(pointSlope, SLOPE_D) || eq(pointSlope, SLOPE_E))
 			cout << "On a line" << endl;
-		else if (y >= 0 && x > 0) { // Check 1st quadrant
-			if (pointSlope > SLOPE_B)
+		else if ((mt(y, 0) || eq(y, 0)) && mt(x, 0)) { // Check 1st quadrant
+			if (mt(pointSlope, SLOPE_B))
 				cout << "Inside green area!" << endl;
-			else if (x > 2.828)
+			else if (mt(x, 2.828))
 				cout << "Inside purple area!" << endl;
 			else
 				cout << "Inside yellow area!" << endl;
 		}
-		else if (y >= 0 && x < 0) { // Check 2nd quadrant
-			if (pointSlope < SLOPE_D)
+		else if ((mt(y, 0) || eq(y, 0)) && lt(x, 0)) { // Check 2nd quadrant
+			if (lt(pointSlope, SLOPE_D))
 				cout << "Inside red area!" << endl;
 			else if (x > -2.828)
 				cout << "Inside pink area!" << endl;
 		}
-		else if (y < 0 && x < 0) { // Check 3rd quadrant
-			if (pointSlope > SLOPE_C)
+		else if (lt(y, 0) && lt(x, 0)) { // Check 3rd quadrant
+			if (mt(pointSlope, SLOPE_C))
 				cout << "Inside blue area!" << endl;
-			else if (x > -2.828)
+			else if (mt(x, -2.828))
 				cout << "Inside pink area!" << endl;
 		}
 		else { // Check 4th quadrant
-			if (pointSlope > SLOPE_E && x > 2.828)
+			if (mt(pointSlope, SLOPE_E) && mt(x, 2.828))
 				cout << "Inside purple area!" << endl;
 			else
 				cout << "Inside yellow area!" << endl;
 		}
 	}
-	else if ((-2.0 < x && x < 2.0) && (-6.0 < y && y < -7.0)) // outside circle and in rectangle
+	else if ((lt(-2, x) && lt(x, 2)) && (lt(-6, y) && lt(y, -7))) // outside circle and in rectangle
 		cout << "Inside grey area" << endl;
 
 }