App Dev Worksheet: Functions

App development lesson 20: Functions · Set 83 · 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 named block of code (b) a type of phone (c) a list of colours (d) a screen size
2.🧰 What does this code show?
function greet(name) {
return "Welcome, " + name + "!";
}
show(greet("Aman")); (a) Welcome, name! (b) Welcome, Aman! (c) Aman (d) greet
3.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(50, 2));
4.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(20, 3));
5.🧰 What does this code show?
function greet(name) {
return "Hi, " + name + "!";
}
show(greet("Meera")); (a) Hi, name! (b) greet (c) Hi, Meera! (d) Meera
6.🧰 What number does this code show?
function triple(n) {
return n * 3;
}
show(triple(4));
7.🧰 What number does this code show?
function triple(n) {
return n * 3;
}
show(triple(38));
8.🧰 Why write a function? (a) to make code longer (b) to slow the app (c) to reuse code (d) to hide errors
9.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(30, 6));
10.🧰 What number does this code show?
function double(n) {
return n * 2;
}
show(double(40));
11.🧰 What number does this code show?
function double(n) {
return n * 2;
}
show(double(3));
12.🧰 What number does this code show?
function triple(n) {
return n * 3;
}
show(triple(33));
13.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(80, 4));
14.🧰 What does return do in a function? (a) sends back a value (b) closes the screen (c) repeats the code (d) deletes the app
15.🧰 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(12));
16.🧰 How do you run (call) a function called greet? (a) run greet (b) #greet (c) greet() (d) greet[]
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(12) + fee(10));
18.🧰 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(6) + fee(4));
19.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(40, 3));
20.🧰 What does this code show?
function greet(name) {
return "Well done, " + name + "!";
}
show(greet("Kabir")); (a) Well done, Kabir! (b) greet (c) Kabir (d) Well done, name!
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(5) + fee(4));
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(5) + fee(1));
23.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(5) + points(0));
24.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(35, 4));
25.🧰 What does this code show?
function greet(name) {
return "Hello, " + name + "!";
}
show(greet("Riya")); (a) Hello, name! (b) greet (c) Hello, Riya! (d) Riya
26.🧰 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));
27.🧰 What number does this code show?
function double(n) {
return n * 2;
}
show(double(27));
28.🧰 What number does this code show?
function points(stars) {
return stars * 10 + 5;
}
show(points(4) + points(5));
29.🧰 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(6) + fee(8));
30.🧰 In function tip(bill), what is bill? (a) a screen (b) a loop (c) a parameter (d) an event
31.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(100, 5));
32.🧰 What does this code show?
function greet(name) {
return "Well done, " + name + "!";
}
show(greet("Meera")); (a) Meera (b) greet (c) Well done, name! (d) Well done, Meera!
33.🧰 What does this code show?
function greet(name) {
return "Well done, " + name + "!";
}
show(greet("Riya")); (a) greet (b) Riya (c) Well done, name! (d) Well done, Riya!
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(5) + fee(11));
35.🧰 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(12) + fee(6));
36.🧰 What number does this code show?
function double(n) {
return n * 2;
}
show(double(37));
37.🧰 What number does this code show?
function double(n) {
return n * 2;
}
show(double(8));
38.🧰 What number does this code show?
function total(price, qty) {
return price * qty;
}
show(total(45, 6));
39.🧰 What number does this code show?
function double(n) {
return n * 2;
}
show(double(34));
40.🧰 What number does this code show?
function triple(n) {
return n * 3;
}
show(triple(9));

Answer key

a named block of code
Welcome, Aman!
100
60
Hi, Meera!
12
114
to reuse code
180
80
6
99
320
sends back a value
60
greet()
120
20
120
Well done, Kabir!
40
50
60
140
Hello, Riya!
0
54
100
40
a parameter
500
Well done, Meera!
Well done, Riya!
80
40
74
16
270
68
27

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