App Dev Worksheet: Functions

App development lesson 20: Functions · Set 694 · 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 20;
}
show(fee(11) + fee(1));
2.🧰 How do you run (call) a function called greet? (a) greet[] (b) run greet (c) greet() (d) #greet
3.🧰 What is a function? (a) a named block of code (b) a type of phone (c) a list of colours (d) a screen size
4.🧰 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(7) + fee(8));
5.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(70, 5));
6.🧰 What number does this code show?
function triple(n) {
return n * 3;
}
show(triple(8));
7.🧰 In function tip(bill), what is bill? (a) a parameter (b) a screen (c) an event (d) a loop
8.🧰 What does this code show?
function greet(name) {
return "Hello, " + name + "!";
}
show(greet("Riya")); (a) Hello, Riya! (b) Riya (c) Hello, name! (d) greet
9.🧰 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!
10.🧰 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(5));
11.🧰 What number does this code show?
function triple(n) {
return n * 3;
}
show(triple(23));
12.🧰 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));
13.🧰 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(12));
14.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(2) + points(4));
15.🧰 What does this code show?
function greet(name) {
return "Well done, " + name + "!";
}
show(greet("Arjun")); (a) Well done, Arjun! (b) Arjun (c) greet (d) Well done, name!
16.🧰 What does return do in a function? (a) closes the screen (b) sends back a value (c) deletes the app (d) repeats the code
17.🧰 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(7) + fee(4));
18.🧰 What number does this code show?
function double(n) {
return n * 2;
}
show(double(35));
19.🧰 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(6) + fee(4));
20.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(70, 6));
21.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(2) + points(5));
22.🧰 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(2) + fee(1));
23.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(5) + points(3));
24.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(20, 4));
25.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(3) + points(0));
26.🧰 What does this code show?
function greet(name) {
return "Hi, " + name + "!";
}
show(greet("Zoya")); (a) Hi, name! (b) Hi, Zoya! (c) greet (d) Zoya
27.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(10, 4));
28.🧰 Why write a function? (a) to hide errors (b) to reuse code (c) to make code longer (d) to slow the app
29.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(2) + points(3));
30.🧰 What number does this code show?
function double(n) {
return n * 2;
}
show(double(32));
31.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(3) + points(3));
32.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(4) + points(1));
33.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(30, 6));
34.🧰 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(7));
35.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(1) + points(4));
36.🧰 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(1));
37.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(4) + points(0));
38.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(2) + points(1));
39.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(4) + points(3));
40.🧰 What does this code show?
function greet(name) {
return "Hello, " + name + "!";
}
show(greet("Meera")); (a) Meera (b) Hello, name! (c) greet (d) Hello, Meera!

Answer key

20
greet()
a named block of code
60
350
24
a parameter
Hello, Riya!
Well done, Zoya!
100
69
40
120
70
Well done, Arjun!
sends back a value
40
70
60
420
80
0
90
80
40
Hi, Zoya!
40
to reuse code
60
64
70
60
180
80
60
0
50
40
80
Hello, Meera!

Free app development lessons, practice and worksheets at talentjr.in/app-development-for-students