website/content/ta/spring2018/cpsc220/feb1.md
2020-01-15 21:51:49 -05:00

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# Lecture for February 1st
## Control Structures
In this class we will talk about three types of control structures
- Sequential
- Selection
- Repetition
Sequential is what is most familiar to us. Write the lines from top to bottom and it executes it in that order
### Selection
Selection depends on the question of `if`.
If it is raining, wear boots
```java
if (raining) {
wearingBoots = true;
}
```
If you want something to happen also when it is not true, consider an `if-else` statement
If the light is off, turn it on.
Otherwise, turn it on
```java
if (lightIsOn) {
lightIsOn = false;
} else {
lightIsOn = true;
}
```
Sometimes you can have multiple branches depending on a condition. Let us take a stop light as an example
```java
if (light == "red") {
car.stop()
} else if (light == "yellow") {
car.slow()
} else {
car.go()
}
```
## String comparison
There is a specific method in the `String` class when it comes to checking for string equality
```java
boolean equals(String s)
```
Let us look at an example
```java
String word = "hello";
boolean ans = word.equals("hello"); // Returns true
boolean ans2 = word.equals("Hello"); // Returns false
```