App Dev Worksheet: Functions

App development lesson 20: Functions · Set 592 · 40 questions

Developer's tip (Write once, use often): function name(parameter) { …; return result; } — call it with name(value). Work out each call separately, then finish the line. Inside a function, if / return can give different results for different inputs.

1. 1.🧰 What number does this code show?
   function total(price, qty) {
     return price * qty;
   }
   show(total(40, 3));
2. 2.🧰 What number does this code show?
   function triple(n) {
     return n * 3;
   }
   show(triple(39));
3. 3.🧰 What number does this code show?
   function triple(n) {
     return n * 3;
   }
   show(triple(30));
4. 4.🧰 What number does this code show?
   function triple(n) {
     return n * 3;
   }
   show(triple(32));
5. 5.🧰 Why write a function? (a) to hide errors (b) to slow the app (c) to make code longer (d) to reuse code
6. 6.🧰 What number does this code show?
   function total(price, qty) {
     return price * qty;
   }
   show(total(50, 5));
7. 7.🧰 What number does this code show?
   function double(n) {
     return n * 2;
   }
   show(double(40));
8. 8.🧰 What is a function? (a) a type of phone (b) a list of colours (c) a named block of code (d) a screen size
9. 9.🧰 A museum app works out the entry fee. What number does this code show?
   function fee(age) {
     if (age < 5) {
       return 0;
     }
     return 20;
   }
   show(fee(10) + fee(11));
10. 10.🧰 What does return do in a function? (a) closes the screen (b) repeats the code (c) sends back a value (d) deletes the app
11. 11.🧰 In function tip(bill), what is bill? (a) a loop (b) a screen (c) a parameter (d) an event
12. 12.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(15, 2));
13. 13.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(80, 4));
14. 14.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(3));
15. 15.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Kabir")); (a) Kabir (b) Well done, Kabir! (c) greet (d) Well done, name!
16. 16.🧰 A museum app works out the entry fee. What number does this code show?
    function fee(age) {
      if (age < 5) {
        return 0;
      }
      return 40;
    }
    show(fee(12) + fee(10));
17. 17.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(29));
18. 18.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Arjun")); (a) Welcome, Arjun! (b) Arjun (c) greet (d) Welcome, name!
19. 19.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(4));
20. 20.🧰 A museum app works out the entry fee. What number does this code show?
    function fee(age) {
      if (age < 5) {
        return 0;
      }
      return 40;
    }
    show(fee(2) + fee(1));
21. 21.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(45, 6));
22. 22.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(85, 5));
23. 23.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(5));
24. 24.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Kabir")); (a) Hi, name! (b) greet (c) Hi, Kabir! (d) Kabir
25. 25.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(65, 3));
26. 26.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(1));
27. 27.🧰 How do you run (call) a function called greet? (a) greet() (b) run greet (c) greet[] (d) #greet
28. 28.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(0));
29. 29.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(40, 4));
30. 30.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(90, 3));
31. 31.🧰 A museum app works out the entry fee. What number does this code show?
    function fee(age) {
      if (age < 5) {
        return 0;
      }
      return 50;
    }
    show(fee(3) + fee(7));
32. 32.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(2));
33. 33.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(12));
34. 34.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(3));
35. 35.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(90, 2));
36. 36.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(28));
37. 37.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(17));
38. 38.🧰 A museum app works out the entry fee. What number does this code show?
    function fee(age) {
      if (age < 5) {
        return 0;
      }
      return 30;
    }
    show(fee(12) + fee(8));
39. 39.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(25));
40. 40.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(30, 2));

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