App Dev Worksheet: Functions

App development lesson 20: Functions · Set 38 · 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 points(stars) {
     return stars * 10 + 5;
   }
   show(points(5) + points(1));
2. 2.🧰 What number does this code show?
   function double(n) {
     return n * 2;
   }
   show(double(8));
3. 3.🧰 What number does this code show?
   function double(n) {
     return n * 2;
   }
   show(double(38));
4. 4.🧰 What number does this code show?
   function total(price, qty) {
     return price * qty;
   }
   show(total(55, 3));
5. 5.🧰 What number does this code show?
   function total(price, qty) {
     return price * qty;
   }
   show(total(45, 5));
6. 6.🧰 What is a function? (a) a named block of code (b) a screen size (c) a type of phone (d) a list of colours
7. 7.🧰 What does return do in a function? (a) deletes the app (b) repeats the code (c) closes the screen (d) sends back a value
8. 8.🧰 What number does this code show?
   function total(price, qty) {
     return price * qty;
   }
   show(total(20, 5));
9. 9.🧰 What does this code show?
   function greet(name) {
     return "Welcome, " + name + "!";
   }
   show(greet("Riya")); (a) Riya (b) Welcome, name! (c) Welcome, Riya! (d) greet
10. 10.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(15, 2));
11. 11.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(25, 2));
12. 12.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(7));
13. 13.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(31));
14. 14.🧰 A museum app works out the entry fee. What number does this code show?
    function fee(age) {
      if (age < 5) {
        return 0;
      }
      return 60;
    }
    show(fee(6) + fee(8));
15. 15.🧰 Why write a function? (a) to hide errors (b) to make code longer (c) to slow the app (d) to reuse code
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 30;
    }
    show(fee(1) + fee(2));
17. 17.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(75, 2));
18. 18.🧰 A museum app works out the entry fee. What number does this code show?
    function fee(age) {
      if (age < 5) {
        return 0;
      }
      return 60;
    }
    show(fee(8) + fee(1));
19. 19.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(17));
20. 20.🧰 In function tip(bill), what is bill? (a) an event (b) a loop (c) a parameter (d) a screen
21. 21.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(5));
22. 22.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(1));
23. 23.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Kabir")); (a) Well done, name! (b) Well done, Kabir! (c) Kabir (d) greet
24. 24.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(20, 3));
25. 25.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(10, 5));
26. 26.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(90, 2));
27. 27.🧰 A museum app works out the entry fee. What number does this code show?
    function fee(age) {
      if (age < 5) {
        return 0;
      }
      return 60;
    }
    show(fee(4) + fee(12));
28. 28.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(8));
29. 29.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(100, 5));
30. 30.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(1));
31. 31.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Zoya")); (a) Zoya (b) Hello, Zoya! (c) greet (d) Hello, name!
32. 32.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(70, 3));
33. 33.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(95, 3));
34. 34.🧰 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(7) + fee(8));
35. 35.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Zoya")); (a) Zoya (b) Hi, name! (c) greet (d) Hi, Zoya!
36. 36.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(32));
37. 37.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(5) + points(0));
38. 38.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(27));
39. 39.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Riya")); (a) Well done, Riya! (b) Well done, name! (c) Riya (d) greet
40. 40.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(45, 4));

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