App Dev Worksheet: Functions

App development lesson 20: Functions · Set 704 · 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.

NameDateTime takenScore ___ / 40

1.🧰 What does return do in a function? (a) repeats the code (b) closes the screen (c) sends back a value (d) deletes the app
2.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(2) + points(2));
3.🧰 What number does this code show?
function triple(n) {
return n * 3;
}
show(triple(33));
4.🧰 How do you run (call) a function called greet? (a) run greet (b) greet[] (c) #greet (d) greet()
5.🧰 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(2) + fee(9));
6.🧰 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(9) + fee(3));
7.🧰 What is a function? (a) a screen size (b) a type of phone (c) a list of colours (d) a named block of code
8.🧰 What does this code show?
function greet(name) {
return "Hi, " + name + "!";
}
show(greet("Meera")); (a) Hi, name! (b) Hi, Meera! (c) greet (d) Meera
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(4) + fee(7));
10.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(60, 2));
11.🧰 Why write a function? (a) to make code longer (b) to reuse code (c) to slow the app (d) to hide errors
12.🧰 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(10) + fee(3));
13.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(3) + points(4));
14.🧰 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(1) + fee(10));
15.🧰 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(2));
16.🧰 What number does this code show?
function double(n) {
return n * 2;
}
show(double(17));
17.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(15, 2));
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(2) + fee(7));
19.🧰 In function tip(bill), what is bill? (a) a loop (b) an event (c) a screen (d) a parameter
20.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(5) + points(0));
21.🧰 What number does this code show?
function triple(n) {
return n * 3;
}
show(triple(23));
22.🧰 What number does this code show?
function triple(n) {
return n * 3;
}
show(triple(36));
23.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(45, 5));
24.🧰 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(4) + fee(9));
25.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(5) + points(2));
26.🧰 What number does this code show?
function double(n) {
return n * 2;
}
show(double(5));
27.🧰 What does this code show?
function greet(name) {
return "Hello, " + name + "!";
}
show(greet("Riya")); (a) Riya (b) Hello, name! (c) greet (d) Hello, Riya!
28.🧰 What does this code show?
function greet(name) {
return "Hi, " + name + "!";
}
show(greet("Arjun")); (a) Hi, Arjun! (b) greet (c) Hi, name! (d) Arjun
29.🧰 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(4) + fee(6));
30.🧰 What number does this code show?
function double(n) {
return n * 2;
}
show(double(23));
31.🧰 What does this code show?
function greet(name) {
return "Well done, " + name + "!";
}
show(greet("Riya")); (a) Well done, name! (b) Riya (c) Well done, Riya! (d) greet
32.🧰 What number does this code show?
function double(n) {
return n * 2;
}
show(double(19));
33.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(1) + points(0));
34.🧰 What number does this code show?
function double(n) {
return n * 2;
}
show(double(15));
35.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(1) + points(2));
36.🧰 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(10) + fee(12));
37.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(90, 6));
38.🧰 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(7));
39.🧰 What number does this code show?
function double(n) {
return n * 2;
}
show(double(29));
40.🧰 What does this code show?
function greet(name) {
return "Well done, " + name + "!";
}
show(greet("Meera")); (a) Meera (b) Well done, name! (c) greet (d) Well done, Meera!

Answer key

sends back a value
50
99
greet()
60
60
a named block of code
Hi, Meera!
20
120
to reuse code
50
80
50
0
34
30
60
a parameter
60
69
108
225
50
80
10
Hello, Riya!
Hi, Arjun!
40
46
Well done, Riya!
38
20
30
40
120
540
40
58
Well done, Meera!

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