App Dev Worksheet: Functions

App development lesson 20: Functions · Set 659 · 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 number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(5) + points(3));
2.🧰 What is a function? (a) a type of phone (b) a list of colours (c) a named block of code (d) a screen size
3.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(85, 3));
4.🧰 What number does this code show?
function double(n) {
return n * 2;
}
show(double(14));
5.🧰 What number does this code show?
function triple(n) {
return n * 3;
}
show(triple(9));
6.🧰 In function tip(bill), what is bill? (a) a loop (b) a screen (c) a parameter (d) an event
7.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(80, 2));
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(5) + fee(11));
9.🧰 What does return do in a function? (a) repeats the code (b) closes the screen (c) deletes the app (d) sends back a value
10.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(90, 6));
11.🧰 What does this code show?
function greet(name) {
return "Welcome, " + name + "!";
}
show(greet("Zoya")); (a) Welcome, Zoya! (b) Zoya (c) greet (d) Welcome, name!
12.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(5) + points(1));
13.🧰 What number does this code show?
function double(n) {
return n * 2;
}
show(double(7));
14.🧰 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(9) + fee(3));
15.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(2) + points(4));
16.🧰 What does this code show?
function greet(name) {
return "Hello, " + name + "!";
}
show(greet("Aman")); (a) Hello, Aman! (b) Aman (c) greet (d) Hello, name!
17.🧰 What does this code show?
function greet(name) {
return "Hello, " + name + "!";
}
show(greet("Riya")); (a) Riya (b) Hello, Riya! (c) Hello, name! (d) greet
18.🧰 What number does this code show?
function triple(n) {
return n * 3;
}
show(triple(27));
19.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(20, 3));
20.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(5) + points(4));
21.🧰 What number does this code show?
function double(n) {
return n * 2;
}
show(double(11));
22.🧰 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(10));
23.🧰 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(1) + fee(2));
24.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(3) + points(3));
25.🧰 What does this code show?
function greet(name) {
return "Hello, " + name + "!";
}
show(greet("Kabir")); (a) Kabir (b) Hello, Kabir! (c) greet (d) Hello, name!
26.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(2) + points(5));
27.🧰 How do you run (call) a function called greet? (a) run greet (b) greet[] (c) greet() (d) #greet
28.🧰 What does this code show?
function greet(name) {
return "Well done, " + name + "!";
}
show(greet("Meera")); (a) Well done, name! (b) Meera (c) greet (d) Well done, Meera!
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(3));
30.🧰 Why write a function? (a) to reuse code (b) to hide errors (c) to make code longer (d) to slow the app
31.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(65, 4));
32.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(85, 2));
33.🧰 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(8));
34.🧰 What number does this code show?
function double(n) {
return n * 2;
}
show(double(12));
35.🧰 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(8));
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(6) + fee(4));
37.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(3) + points(1));
38.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(4) + points(5));
39.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(3) + points(0));
40.🧰 What number does this code show?
function double(n) {
return n * 2;
}
show(double(40));

Answer key

90
a named block of code
255
28
27
a parameter
160
100
sends back a value
540
Welcome, Zoya!
70
14
40
70
Hello, Aman!
Hello, Riya!
81
60
100
22
40
0
70
Hello, Kabir!
80
greet()
Well done, Meera!
0
to reuse code
260
170
20
24
100
50
50
100
40
80

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