I get a strange problem on some android phones, when I run the code below. public void test(){ int num = 1; for(int i=0;i<14;i++){ num = num+100000; } System.out.println("num "+num); }
I expect the answer "1400001", but I get the wrong answer "200385" on the phone like MotoX 2ndGen, Xiaomi3, Xiaomi note etc. The strangest thing is that I can get the right answer when I want to debug it, or complicate the code like public void test(){ int num = 1; for(int i=0;i<14;i++){ num = num+100000; System.out.println("num "+num); } } or public void test(){ int num1 = 1; for(int i=0;i<14;i++){ num1 = num1+100000; } System.out.println("num1 "+num1); int num2 = 1; for(int i=0;i<14;i++){ num2 = num2+100000; } System.out.println("num2 "+num2); } or turn `int` to `long`, or make "100000" to 100, it can get the right answer usually. So what is the reason behind this phenomenon? An integer overflow maybe? supplement: I test Integer.SIZE <https://developer.android.com/reference/java/lang/Integer.html#SIZE> on the wrong phones is 32 , and the Integer.MAX_VALUE <https://developer.android.com/reference/java/lang/Integer.html#MAX_VALUE> is 2147483647,as others.And I find that one of results would overflow on "131072" ,changing to binary is 2^17.And all of the wrong result occur on fourfold times in "for" code,like the fourth , the eighth etc.so why? -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To unsubscribe from this group and stop receiving emails from it, send an email to android-developers+unsubscr...@googlegroups.com. To post to this group, send email to android-developers@googlegroups.com. Visit this group at https://groups.google.com/group/android-developers. To view this discussion on the web visit https://groups.google.com/d/msgid/android-developers/d5ba839d-d711-429f-9acb-7fc92437788c%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.