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I have the following code:
if (this->_car.getAbsoluteAngle() <= 30 || this->_car.getAbsoluteAngle() >= 330) this->_car.edir = Car::EDirection::RIGHT; else if (this->_car.getAbsoluteAngle() > 30 && this->_car.getAbsoluteAngle() <= 60) this->_car.edir = Car::EDirection::UP_RIGHT; else if (this->_car.getAbsoluteAngle() > 60 && this->_car.getAbsoluteAngle() <= 120) this->_car.edir = Car::EDirection::UP; else if (this->_car.getAbsoluteAngle() > 120 && this->_car.getAbsoluteAngle() <= 150) this->_car.edir = Car::EDirection::UP_LEFT; else if (this->_car.getAbsoluteAngle() > 150 && this->_car.getAbsoluteAngle() <= 210) this->_car.edir = Car::EDirection::LEFT; else if (this->_car.getAbsoluteAngle() > 210 && this->_car.getAbsoluteAngle() <= 240) this->_car.edir = Car::EDirection::DOWN_LEFT; else if (this->_car.getAbsoluteAngle() > 240 && this->_car.getAbsoluteAngle() <= 300) this->_car.edir = Car::EDirection::DOWN; else if (this->_car.getAbsoluteAngle() > 300 && this->_car.getAbsoluteAngle() <= 330) this->_car.edir = Car::EDirection::DOWN_RIGHT; I want to avoid the ifs chain; it's really ugly. Is there a another, possibly cleaner, way of writing this?
445
Avoid using nested if-else statements. Keep the code linear and straightforward. Utilize creating functions/methods. Compare it when we try to use an if-else statement that is nested and that does not utilize the power of the return statement, We get this (Code 1.4).
If you are getting an error about the else it is because you've told the interpreter that the ; was the end of your if statement so when it finds the else a few lines later it starts complaining. A few examples of where not to put a semicolon: if (age < 18); if ( 9 > 10 ); if ("Yogi Bear". length < 3); if ("Jon".
Overview. If else statements are used for decision making, by specifying which block of code is to be executed when a certain condition is met. Nested if else statements are just if else statements inside other if else statements to provide better decision making.
IF-ELSE-IF: if the condition is true, then the block of code inside the IF statement is executed. After that, the ELSE-IF block is checked. If the condition associated with this is true, then the block of statements inside this ELSE-IF block is executed. Otherwise, the statement inside the ELSE block is executed.
#include <iostream> enum Direction { UP, UP_RIGHT, RIGHT, DOWN_RIGHT, DOWN, DOWN_LEFT, LEFT, UP_LEFT }; Direction GetDirectionForAngle(int angle) { const Direction slices[] = { RIGHT, UP_RIGHT, UP, UP, UP_LEFT, LEFT, LEFT, DOWN_LEFT, DOWN, DOWN, DOWN_RIGHT, RIGHT }; return slices[(((angle % 360) + 360) % 360) / 30]; } int main() { // This is just a test case that covers all the possible directions for (int i = 15; i < 360; i += 30) std::cout << GetDirectionForAngle(i) << ' '; return 0; } This is how I would do it. (As per my previous comment).
193
You can use map::lower_bound and store the upper-bound of each angle in a map.
Working example below:
#include <cassert> #include <map> enum Direction { RIGHT, UP_RIGHT, UP, UP_LEFT, LEFT, DOWN_LEFT, DOWN, DOWN_RIGHT }; using AngleDirMap = std::map<int, Direction>; AngleDirMap map = { { 30, RIGHT }, { 60, UP_RIGHT }, { 120, UP }, { 150, UP_LEFT }, { 210, LEFT }, { 240, DOWN_LEFT }, { 300, DOWN }, { 330, DOWN_RIGHT }, { 360, RIGHT } }; Direction direction(int angle) { assert(angle >= 0 && angle <= 360); auto it = map.lower_bound(angle); return it->second; } int main() { Direction d; d = direction(45); assert(d == UP_RIGHT); d = direction(30); assert(d == RIGHT); d = direction(360); assert(d == RIGHT); return 0; } If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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