App Dev Worksheet: Functions

App development lesson 20: Functions · Set 713 · 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.🧰 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(2) + fee(8));
2.🧰 What is a function? (a) a screen size (b) a type of phone (c) a list of colours (d) a named block of code
3.🧰 What does return do in a function? (a) closes the screen (b) sends back a value (c) repeats the code (d) deletes the app
4.🧰 What does this code show?
function greet(name) {
return "Hello, " + name + "!";
}
show(greet("Meera")); (a) Meera (b) Hello, name! (c) Hello, Meera! (d) greet
5.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(35, 3));
6.🧰 What does this code show?
function greet(name) {
return "Hi, " + name + "!";
}
show(greet("Meera")); (a) greet (b) Hi, name! (c) Hi, Meera! (d) Meera
7.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(1) + points(3));
8.🧰 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(11) + fee(12));
9.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(15, 6));
10.🧰 What number does this code show?
function double(n) {
return n * 2;
}
show(double(7));
11.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(20, 6));
12.🧰 Why write a function? (a) to make code longer (b) to hide errors (c) to reuse code (d) to slow the app
13.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(4) + points(5));
14.🧰 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(6));
15.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(10, 5));
16.🧰 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));
17.🧰 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(4));
18.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(65, 3));
19.🧰 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(11) + fee(1));
20.🧰 What does this code show?
function greet(name) {
return "Well done, " + name + "!";
}
show(greet("Riya")); (a) Well done, Riya! (b) Riya (c) Well done, name! (d) greet
21.🧰 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(11) + fee(1));
22.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(2) + points(2));
23.🧰 What number does this code show?
function triple(n) {
return n * 3;
}
show(triple(4));
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(10));
25.🧰 How do you run (call) a function called greet? (a) run greet (b) #greet (c) greet[] (d) greet()
26.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(1) + points(0));
27.🧰 What number does this code show?
function double(n) {
return n * 2;
}
show(double(20));
28.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(95, 6));
29.🧰 What does this code show?
function greet(name) {
return "Well done, " + name + "!";
}
show(greet("Arjun")); (a) greet (b) Arjun (c) Well done, Arjun! (d) Well done, name!
30.🧰 In function tip(bill), what is bill? (a) a loop (b) an event (c) a parameter (d) a screen
31.🧰 What number does this code show?
function triple(n) {
return n * 3;
}
show(triple(13));
32.🧰 What number does this code show?
function double(n) {
return n * 2;
}
show(double(5));
33.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(5) + points(2));
34.🧰 What does this code show?
function greet(name) {
return "Well done, " + name + "!";
}
show(greet("Aman")); (a) greet (b) Aman (c) Well done, name! (d) Well done, Aman!
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(5));
36.🧰 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(1));
37.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(3) + points(0));
38.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(2) + points(4));
39.🧰 What number does this code show?
function triple(n) {
return n * 3;
}
show(triple(12));
40.🧰 What number does this code show?
function double(n) {
return n * 2;
}
show(double(10));

Answer key

50
a named block of code
sends back a value
Hello, Meera!
105
Hi, Meera!
50
100
90
14
120
to reuse code
100
60
50
40
0
195
20
Well done, Riya!
40
50
12
50
greet()
20
40
570
Well done, Arjun!
a parameter
39
10
80
Well done, Aman!
80
0
40
70
36
20

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