Using string taken from Scanner not working?
When I run the program and enter a rank & gender it yells at me and tells me it is an invalid gender. I cannot see why if I enter "male" into the console, it does not equal the string "male"? Can please explain to me why this doesn't work and perhaps some suggestions on how to fix it? Thanks!
import java.io.File;
import java.io.IOException;
import java.util.Scanner;
public class BabyNames {
public static void main(String[] args) throws IOException {
Scanner input = new Scanner(System.in);
System.out.print("Enter male or female: ");
String gender1 = input.next();
System.out.print("Enter rank: ");
int rank = input.nextInt();
while (!(gender1 == "female" || gender1 == "male")){
System.out.println("Please try again with a valid gender.");
System.out.println("");
System.out.println("Enter male or fem开发者_高级运维ale: ");
gender1 = input.next();
}
while (rank <= 0 || rank > 1000){
System.out.println("Please try again with a valid rank.");
System.out.println("");
System.out.println("Enter rank: ");
rank = input.nextInt();
}
findRank(gender1, rank);
}
public static void findRank(String gender2, int rank) throws IOException {
File babyNames = new File("/home/skatty14/Downloads/BabyNames.txt");
Scanner input = new Scanner(babyNames);
int rankCount = 0;
while (input.hasNextLine()){
rankCount++;
System.out.println(rankCount);
if (gender2 == "male"){
String name = input.next();
System.out.println(name);
}
if (gender2 == "female"){
String name = input.next();
System.out.println(name);
}
}
}
}
To compare Strings
, you need to use .equals()
so change all of your String comparisons with ==
to use .equals()
instead.
if(gender1 == "male") { ... }
would become,
if(gender1.equals("male")) { ... }
So on and so forth.
The '==' operator tests for equivalence of references to Strings, not contents of Strings, hence why your code is not giving you the expected results.
Try using the form
if (gender1.equals("female"))
etc. instead.
Anthony Forloney answer is the best
but you can skip the equals, if you want, with intern() function provided by String API.
if( gender1.intern() == "male".intern() ) { ... }
intern
public String intern() Returns a canonical representation for the string object.
A pool of strings, initially empty, is maintained privately by the class String.
When the intern method is invoked, if the pool already contains a string equal to this String object as determined by the equals(Object) method, then the string from the pool is returned. Otherwise, this String object is added to the pool and a reference to this String object is returned.
It follows that for any two strings s and t, s.intern() == t.intern() is true if and only if s.equals(t) is true.
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