App Dev Worksheet: Functions

App development lesson 20: Functions · Set 425 · 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(100, 4));
2. 2.🧰 What number does this code show?
   function triple(n) {
     return n * 3;
   }
   show(triple(26));
3. 3.🧰 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(12) + fee(4));
4. 4.🧰 What number does this code show?
   function total(price, qty) {
     return price * qty;
   }
   show(total(70, 6));
5. 5.🧰 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(12) + fee(4));
6. 6.🧰 What does this code show?
   function greet(name) {
     return "Well done, " + name + "!";
   }
   show(greet("Kabir")); (a) Well done, name! (b) greet (c) Well done, Kabir! (d) Kabir
7. 7.🧰 What number does this code show?
   function points(stars) {
     return stars * 10 + 5;
   }
   show(points(1) + points(4));
8. 8.🧰 What number does this code show?
   function total(price, qty) {
     return price * qty;
   }
   show(total(60, 3));
9. 9.🧰 What number does this code show?
   function points(stars) {
     return stars * 10 + 5;
   }
   show(points(5) + points(2));
10. 10.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Aman")); (a) Welcome, name! (b) greet (c) Welcome, Aman! (d) Aman
11. 11.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(37));
12. 12.🧰 How do you run (call) a function called greet? (a) run greet (b) greet() (c) greet[] (d) #greet
13. 13.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(10, 4));
14. 14.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Zoya")); (a) Hi, name! (b) Hi, Zoya! (c) greet (d) Zoya
15. 15.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(4));
16. 16.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(6));
17. 17.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(7));
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 40;
    }
    show(fee(6) + fee(6));
19. 19.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Zoya")); (a) Well done, name! (b) Zoya (c) Well done, Zoya! (d) greet
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 20;
    }
    show(fee(5) + fee(8));
21. 21.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(3));
22. 22.🧰 What is a function? (a) a screen size (b) a named block of code (c) a type of phone (d) a list of colours
23. 23.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(60, 2));
24. 24.🧰 What does return do in a function? (a) sends back a value (b) closes the screen (c) repeats the code (d) deletes the app
25. 25.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(80, 2));
26. 26.🧰 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(9) + fee(1));
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 20;
    }
    show(fee(3) + fee(5));
28. 28.🧰 Why write a function? (a) to make code longer (b) to reuse code (c) to slow the app (d) to hide errors
29. 29.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(65, 5));
30. 30.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(45, 6));
31. 31.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(65, 4));
32. 32.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(35, 3));
33. 33.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(9));
34. 34.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(13));
35. 35.🧰 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(2));
36. 36.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(27));
37. 37.🧰 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(7) + fee(7));
38. 38.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(35, 6));
39. 39.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(4));
40. 40.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(6));

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