App Dev Worksheet: Functions

App development lesson 20: Functions · Set 491 · 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 is a function? (a) a type of phone (b) a screen size (c) a named block of code (d) a list of colours
2.🧰 How do you run (call) a function called greet? (a) greet() (b) #greet (c) greet[] (d) run greet
3.🧰 What number does this code show?
function double(n) {
return n * 2;
}
show(double(29));
4.🧰 What number does this code show?
function double(n) {
return n * 2;
}
show(double(20));
5.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(40, 6));
6.🧰 Why write a function? (a) to reuse code (b) to hide errors (c) to make code longer (d) to slow the app
7.🧰 What does this code show?
function greet(name) {
return "Welcome, " + name + "!";
}
show(greet("Riya")); (a) Welcome, Riya! (b) Welcome, name! (c) Riya (d) greet
8.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(5) + points(3));
9.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(3) + points(4));
10.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(1) + points(3));
11.🧰 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(1) + fee(6));
12.🧰 What does this code show?
function greet(name) {
return "Welcome, " + name + "!";
}
show(greet("Kabir")); (a) Welcome, Kabir! (b) Welcome, name! (c) greet (d) Kabir
13.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(5) + points(5));
14.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(95, 6));
15.🧰 In function tip(bill), what is bill? (a) a loop (b) an event (c) a screen (d) a parameter
16.🧰 What number does this code show?
function triple(n) {
return n * 3;
}
show(triple(5));
17.🧰 What does return do in a function? (a) deletes the app (b) sends back a value (c) repeats the code (d) closes the screen
18.🧰 What does this code show?
function greet(name) {
return "Hello, " + name + "!";
}
show(greet("Kabir")); (a) Hello, name! (b) greet (c) Kabir (d) Hello, Kabir!
19.🧰 What number does this code show?
function triple(n) {
return n * 3;
}
show(triple(31));
20.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(35, 4));
21.🧰 What number does this code show?
function triple(n) {
return n * 3;
}
show(triple(28));
22.🧰 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(1));
23.🧰 What number does this code show?
function triple(n) {
return n * 3;
}
show(triple(3));
24.🧰 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(10) + fee(3));
25.🧰 What does this code show?
function greet(name) {
return "Well done, " + name + "!";
}
show(greet("Meera")); (a) Well done, name! (b) Meera (c) Well done, Meera! (d) greet
26.🧰 What number does this code show?
function double(n) {
return n * 2;
}
show(double(39));
27.🧰 What number does this code show?
function double(n) {
return n * 2;
}
show(double(28));
28.🧰 What number does this code show?
function double(n) {
return n * 2;
}
show(double(34));
29.🧰 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(11) + fee(3));
30.🧰 What does this code show?
function greet(name) {
return "Hi, " + name + "!";
}
show(greet("Zoya")); (a) Zoya (b) Hi, Zoya! (c) greet (d) Hi, name!
31.🧰 What number does this code show?
function triple(n) {
return n * 3;
}
show(triple(4));
32.🧰 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(11));
33.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(1) + points(4));
34.🧰 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(8));
35.🧰 What does this code show?
function greet(name) {
return "Welcome, " + name + "!";
}
show(greet("Aman")); (a) Welcome, name! (b) Welcome, Aman! (c) Aman (d) greet
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(4) + fee(4));
37.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(2) + points(3));
38.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(75, 3));
39.🧰 What does this code show?
function greet(name) {
return "Well done, " + name + "!";
}
show(greet("Riya")); (a) greet (b) Riya (c) Well done, Riya! (d) Well done, name!
40.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(2) + points(1));

Answer key

a named block of code
greet()
58
40
240
to reuse code
Welcome, Riya!
90
80
50
20
Welcome, Kabir!
110
570
a parameter
15
sends back a value
Hello, Kabir!
93
140
84
50
9
40
Well done, Meera!
78
56
68
60
Hi, Zoya!
12
80
60
40
Welcome, Aman!
0
60
225
Well done, Riya!
40

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