If/Else
Types we know
// int
var cupsOfWater = 5;
// double
var tip = 13.45;
// string
var dayOfWeek = "Tuesday";
boolean
var needCoffee = true;
var hungry = false;
Now that we tools to store a yes or no value, we can have our programs make decisions
"if" statements allow our programs to make basic decisions based on a yes or no value
if statements
var coffeeCupIsEmpty = true
if (coffeeCupIsEmpty) {
// re fill coffee
} else {
// Drink Cofee
}
// Get work done
Boolean expression
Comparing
var redCrayons = 10;
var blueCrayons = 7;
var w = redCrayons > blueCrayons; // true
var x = redCrayons >= blueCrayons; // true
var y = redCrayons < blueCrayons; // false
var z = redCrayons <= blueCrayons; // false
Equality
var currentScore = 10
var target = 15
var isEqual = currentScore == target; // false
Simple if
var animal = Console.ReadLine();
var habitat = "the city";
if (animal == "ox"){
habitat = "the farm";
}
else
var animal = Console.ReadLine();
var habitat = "the city";
if (animal == "ox"){
habitat = "the farm";
} else {
habitat = "woods";
}
else if
var animal = Console.ReadLine();
var habitat = "the city";
if (animal == "ox"){
habitat = "the farm";
} else if (animal == "moose"){
habitat = "tundra";
} else {
habitat = "woods";
}
They stack!
var animal = Console.ReadLine();
var habitat = "the city";
if (animal == "ox"){
habitat = "the farm";
} else if (animal == "moose"){
habitat = "tundra";
} else if (animal == "otter"){
habitat = "river";
} else if (animal == "sea tutle"){
habitat = "sea";
} else {
habitat = "woods";
}
boolean logic
var niceOutside = sunny && notTooHot;
var shouldIwatchAMovie = GoodMovie || Raining;
var isNight= !isDay;
don't be scared, might get a bit math-y
Truth tables
A | B | Result |
---|---|---|
T | T | T |
T | F | F |
F | T | F |
F | F | F |
A && B
Truth tables
A | B | Result |
---|---|---|
T | T | T |
T | F | T |
F | T | T |
F | F | F |
A || B
Sample if
const ringsToDestroy = Console.ReadLine();
const ringBearer = Console.ReadLine();
if (ringsToDestroy > 0 && ringBearer == "Frodo"){
// Keep walking
} else if (ringsToDestroy == 0){
// relax in the Shire
} else if (ringBearer != "Frodo") {
// Find the ring!
}
How are we feeling?
Expand the Tip Calculator!
If/Else C#
By Mark Dewey
If/Else C#
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