c# · level 1 · unit 4 · lesson 2
- meet it
- guess first
- your turn
- fix it
- nailed it
Tap a green word if you get lost.
meet it
is the other path at the fork.
An if on its own either runs its block or skips it. Often you want a plan B. else means otherwise: when the condition is false, C# runs the else block instead.
At a fork you always take exactly one path. With if and else, exactly one block runs. Never both, and never neither.
else goes on the line straight after the closing curly bracket of the if. It has no condition of its own, and its lines sit in their own block.
using System;
int biscuits = 0;
if (biscuits == 0)
{
Console.WriteLine("Time to go to the shop.");
}
else
{
Console.WriteLine("Have a biscuit!");
} Read else as otherwise.
guess first
No lives left. Make a guess.
Guess before you run it. Wrong guesses are how you learn, and nothing is marked.
using System;
int lives = 0;
bool gameOver = lives == 0;
if (gameOver)
{
Console.WriteLine("Game over!");
}
else
{
Console.WriteLine("Keep playing!");
}
your turn
Your turn. Meet a pet that is not a dog.
Type any pet except a dog between the quotes, then press run to see plan B.
output
press run to see what happens
fix it
The cinema code will not run. Fix it!
output
press run to see what happens
- C# says
elsecannot start a statement. Look at the very end of line 4. - A semicolon ends an instruction, so the
ifstops right there, before its block. Nowelsehas noifto pair with. - Delete the
;at the end of line 4, then press run.
nailed it
your program has a plan b now. :D
elseruns when theifcondition isfalse.- Only one block runs: the
ifblock or theelseblock. - Never put a semicolon straight after the
ifbrackets.
new words in your collection
- else
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