2020-01-15 23:07:02 -05:00
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2022-02-15 01:14:58 -05:00
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2020-01-15 23:07:02 -05:00
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< h1 > Lecture for February 8th< / h1 >
< h2 > Switch Statements< / h2 >
< p > Another way to perform multiway branching. Comparing a variable and constant values (< code > String< / code > , < code > int< / code > , < code > char< / code > )< / p >
< p > Switch statements cannot be used with < code > boolean< / code > , < code > double< / code > , or < code > float< / code > s< / p >
< h3 > Syntax< / h3 >
< pre > < code class = "language-java" > switch (variable) {
case value1:
// Do something
break;
case value2:
// Do something else
break;
//...
default:
// If all else fails do this
break;
}< / code > < / pre >
< p > < code > case< / code > is a reserved word that means " when our variable in consideration is equal to..." < / p >
< p > If you forget the < code > break< / code > keyword, then the program will keep doing the work of all the statements until it hits a < code > break< / code > keyword.< / p >
< h3 > Example Switch Syntax< / h3 >
< pre > < code class = "language-java" > switch (birthday) {
case 1:
birthstone = "garnet";
break;
case 2:
birthstone = "amethyst";
break;
// ....
default:
System.out.println("Not valid");
break;
}< / code > < / pre >
< h2 > Comparing Strings Relationally< / h2 >
< p > Comparing strings are based on the ASCII value of characters< / p >
< p > Sorting strings will result in strings being in alphabetical or reverse alphabetical order. The values of the strings are compared character by character from the left with each ASCII value.< / p >
< p > To compare strings use the < code > compareTo()< / code > method. Here is the format of the call< / p >
< pre > < code class = "language-java" > str1.compareTo(str2)< / code > < / pre >
< p > This returns a < em > negative number< / em > when < code > str1< / code > is less than < code > str2< / code > < / p >
< p > This returns < code > 0< / code > when < code > str1< / code > is equal to < code > str1< / code > < / p >
< p > This returns a < em > positive number< / em > when < code > str1< / code > is greater than < code > str2< / code > < / p >
< h3 > Example< / h3 >
< pre > < code class = "language-java" > String a = "apple";
String b = "banana";
int x = a.compareTo(b); // x = -1
int y = b.compareTo(a); // y = 1< / code > < / pre >
< h2 > Ternary Operator< / h2 >
< p > With a ternary operator, you can shorten statements where a value is determined by an if statement< / p >
< pre > < code class = "language-java" > String output = "";
if (movieRating > 4) {
output = "Fan favorite";
} else {
output = "Alright";
}< / code > < / pre >
< p > Is equivalent to< / p >
< pre > < code class = "language-java" > String output = "";
output = (movieRating > 4)? "Fan favorite": "Alright";< / code > < / pre >
< h3 > Another Example< / h3 >
< pre > < code class = "language-java" > double shipping;
if (isPrimeMember) {
shipping = 0;
} else {
shipping = 3.99;
}< / code > < / pre >
< p > Is equivalent to< / p >
< pre > < code class = "language-java" > double shipping = (isPrimeMember)? 0: 3.99;< / code > < / pre >
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