Which codes are more efficient?

[perfectlifepan]

1a) for(int i=0;i<100;i++){
     if(a == 0 && a==1)//a is int
     System.out.println("abc");
   }
 b) for(int i=0;i<100;i++){
      if(a != 0 || a!=1)continue;
      System.out.println("abc");
     }

2a) for(int i=0;i<100;i++){
     System.out.println (this.getObject1().getObject2().getText());
   }
 b)
     Object2 o2 = this.getObject1().getObject2();
     for(int i=0;i<100;i++){
      System.out.println(o2.getText());
     }

3a) for(int i=0;i<100;i++){
     if(str.equal("1"))
     System.out.println("str");
   }
 b) for(int i=0;i<100;i++){
      if(Integer.parseInt(str) == 1)
      System.out.println("str");
     }
 c) for(int i=0;i<100;i++){
      if(str.charAt(0) == '1')
      System.out.println("str");
     }

[oNyx]

a) use a profiler
b) all of those versions are about equally slow/fast... the most time is spend in the print method

[Linuxhippy]

to be honest ... if you're lonely try to find someone in a chatroom...

Games published by our own members! Check 'em out!

[Vorax]

There is an answer for each, but it looks to much like some kind of homework for me to give em.

[princec]

to be honest ... if you're lonely try to find someone in a chatroom...

Or, er, get out more and try to meet some girls

Cas

[blahblahblahh]

1a)
     if(a == 0 && a==1)

Interesting...

ANywy, the answer is "they're all the same" except one.

[Markus_Persson]

That CAN return true with some tricky threading and some luck.

[Abuse]

1 will be fastest, if a is null

[blahblahblahh]

That CAN return true with some tricky threading and some luck.

Dang. Fair enough

When replying, I momentarily wonderd if the compiler would compile it out, and then remembered:

1   2   3   4   5

void blah() throws Exception { throw new Exception(); String a = "poor little me"; }

...does not compile, but:

1   2   3   4   5   6

void blah() throws Exception { if( true )   throw new Exception(); String a = "poor little me"; }

does. And so does:

1   2   3   4   5   6

void blah() throws Exception { if( 1 == 1 )    throw new Exception(); String a = "poor little me"; }

...so, hotspot might compile it out, but it's far from assured .

[mikelomax]

Depends what he means by efficient and what the job is that you want it to do as if it doesn't do the right job, it isn't that efficient.