java - Q: Simple Loop Tracing -

i'm not sure happens "num2", "num1" times every number 1-4 times every number 1-4 have no idea "num2"

int num1 = 0; int num2 = 0:  (var = 0; <= 4; i++){           num1 = * i;           num2 += num1;           system.out.println(num1 + " "); }  system.out.println(num2); 

so question trace "num2"? appreciated!

in case, following true:

num1 equal whatever index is, multiplied itself. therefore run on 0, 1, 2, 3 , 4 starts 0 , runs until less or equal 4.

therefore, num1 be:

1) 0 * 0 = 0 2) 1 * 1 = 1 3) 2 * 2 = 4 4) 3 * 3 = 9 5) 4 * 4 = 16 

then num2 calculates sum of each of these, be:

0 + 1 + 4 + 9 + 16 = 30 

this broken into:

before loop: num2 = 0  1) num2 = 0 + 0 = 0 2) num2 = 0 + 1 = 1 3) num2 = 1 + 4 = 5 4) num2 = 5 + 9 = 14 5) num2 = 14 + 16 = 30 

it adding whatever num1 total far.

hope clarifes bit.

edit:

as sharonbn has mentioned, var not valid type in java, should 'int'.

also, have:

int num2 = 0: 

here have ended colon (:) should semi-colon (;).