In Java, how do you check if a command line argument is equal to a string?
I'm learning the Java programming language and I have come to a rut in the road. Below is the simple "Hello Rusty" program, I want it do its usual thing, but if the argument is a certain word/number (42 in this case) it says something totally different. There are no errors while compiling the code, just when I type
"java hello 42"
the outcome is
"Hello 42"
Instead of the expected
"You have greeted the answer to life, the universe, and everything,
you deserve some cake."
I am almost certain the problem is in line 2, line 5 or both.
1 class hello{
2 public static void main (String args[]){
3 /*Now let us say Hello*/
4 if (args.length > 0) {
5 if (args[0] == "42") {
6 System.out.println("You have greeted the answer to life, the universe, and everything,");
7 System.out.println("you deserve some cake.");
8 }
9 else{
10 System.out.println("Hello " + args[0] + "!");
11 }
12 }
13 else{
14 System.out.println("Hello whoever you are!");
15 }
16 }
17}
Thank you in advance for the help
Discussions
Best Answer 7 years ago
You either need to convert args[0] to an integer, or use the string object's "compareTo" method. So either
Integer.parseInt(args[0]) == 42
or
args[0].compareTo("42") == 0
inside your if statement.
Answer 7 years ago
Thanks, I tried them both and the second one worked great!
For everyone else who is trying to get something out of this question, I found that it also works with a string, not just and integer. here is my fixed code.
class hello{
public static void main (String args[]){
/*Now let us say Hello*/
if (args.length > 0) {
if (args[0].compareTo("thing") == 0) {
System.out.println("You have greeted the answer to life, the uni...,");
System.out.println("you deserve some cake, or pie.");
}
else{
System.out.println("Hello " + args[0] + "!");
}
}
else{
System.out.println("Hello whoever you are!");
}
}
}
Thanks again drknotter!