App Dev Worksheet: Functions

App development lesson 20: Functions · Set 249 · 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) sends back a value (c) closes the screen (d) deletes the app
2.🧰 What number does this code show?
function double(n) {
return n * 2;
}
show(double(18));
3.🧰 What is a function? (a) a list of colours (b) a named block of code (c) a screen size (d) a type of phone
4.🧰 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(10));
5.🧰 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(7) + fee(4));
6.🧰 What number does this code show?
function double(n) {
return n * 2;
}
show(double(6));
7.🧰 What does this code show?
function greet(name) {
return "Hi, " + name + "!";
}
show(greet("Meera")); (a) Meera (b) greet (c) Hi, name! (d) Hi, Meera!
8.🧰 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(5) + fee(8));
9.🧰 What number does this code show?
function double(n) {
return n * 2;
}
show(double(4));
10.🧰 How do you run (call) a function called greet? (a) run greet (b) #greet (c) greet[] (d) greet()
11.🧰 What does this code show?
function greet(name) {
return "Well done, " + name + "!";
}
show(greet("Kabir")); (a) greet (b) Kabir (c) Well done, name! (d) Well done, Kabir!
12.🧰 Why write a function? (a) to hide errors (b) to make code longer (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(1) + points(1));
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(9) + fee(3));
15.🧰 What number does this code show?
function triple(n) {
return n * 3;
}
show(triple(5));
16.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(3) + points(5));
17.🧰 What number does this code show?
function double(n) {
return n * 2;
}
show(double(15));
18.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(75, 6));
19.🧰 What does this code show?
function greet(name) {
return "Well done, " + name + "!";
}
show(greet("Zoya")); (a) greet (b) Well done, Zoya! (c) Zoya (d) Well done, name!
20.🧰 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(5) + fee(10));
21.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(3) + points(0));
22.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(2) + points(3));
23.🧰 What number does this code show?
function triple(n) {
return n * 3;
}
show(triple(21));
24.🧰 What number does this code show?
function triple(n) {
return n * 3;
}
show(triple(34));
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 points(stars) {
return stars * 10 + 5;
}
show(points(1) + points(5));
27.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(80, 6));
28.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(25, 2));
29.🧰 What does this code show?
function greet(name) {
return "Well done, " + name + "!";
}
show(greet("Aman")); (a) Well done, Aman! (b) Aman (c) greet (d) Well done, name!
30.🧰 In function tip(bill), what is bill? (a) an event (b) a loop (c) a screen (d) a parameter
31.🧰 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(8) + fee(12));
32.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(1) + points(2));
33.🧰 What does this code show?
function greet(name) {
return "Hi, " + name + "!";
}
show(greet("Riya")); (a) greet (b) Riya (c) Hi, Riya! (d) Hi, name!
34.🧰 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(1));
35.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(5) + points(1));
36.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(45, 6));
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(2) + fee(7));
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(8) + fee(4));
39.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(85, 6));
40.🧰 What does this code show?
function greet(name) {
return "Well done, " + name + "!";
}
show(greet("Meera")); (a) Meera (b) Well done, Meera! (c) greet (d) Well done, name!

Answer key

sends back a value
36
a named block of code
60
50
12
Hi, Meera!
120
8
greet()
Well done, Kabir!
to reuse code
30
60
15
90
30
450
Well done, Zoya!
100
40
60
63
102
80
70
480
50
Well done, Aman!
a parameter
40
40
Hi, Riya!
0
70
270
20
20
510
Well done, Meera!

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