java - What exactly does this piece of code do? -

i beginner programmer,

i have array called myarray , wanting know if statment in code does. myarray[count] do?

         for(int = 0; < count; i++)              if (number == myarray[i])             {             containsnumber = true;             }              if ( !containsnumber )             {                myarray [ count ] = number;                count++;             } // end if 

cheers

notice

because code not complete have assumptions:

• all variables declared , initalized before
• count represents number of elements in array
• the array sufficiently sized
• containsnumber initalized false

short

it checks if given number exists in array , if not add it.

explained

at first, make bit more readable can add 2 braces after instruction:

for(int = 0; < count; i++) {     if (number == myarray[i])     {         containsnumber = true;     } }  if ( !containsnumber ) {    myarray [ count ] = number;    count++; } // end if 

because there no breaces after for affect following statement or block, if statement.

at first code loop through array , check every position smaller count (value of i ) given number.

if value found (if (number == myarray[i])) variable containsnumber set true.

after iterating on array variable containsnumber checked.

an if statement must contain boolean value, can write if (containsnumber) instead of if (containsnumber == true).

the ! negates boolean value. means check if containsnumber not true. if (containsnumber != true) or if (containsnumber == false) same.

if number not in array (containsnumber false) added @ next position (myarray [ count ] = number;) , count incremented 1 (count++;).

example

let's array contains values 1, 5 , 7. number has value 4 , count 3 because array contains 3 elements.

for loop:

first iteration

i has value 0 --> 0 smaller 3 (count)

if (number == myarray[i]) --> if (4 == myarray[0]) --> if (4 == 1)

--> false

second iteration

i has value 1 --> 1 smaller 3 (count)

if (number == myarray[i]) --> if (4 == myarray[1]) --> if (4 == 5)

--> false

third iteration

i has value 2 --> 2 smaller 3 (count)

if (number == myarray[i]) --> if (4 == myarray[2]) --> if (4 == 7)

--> false

fourth iteration

i has value 3 --> 3 not smaller 3 (count)

for ends

next step

containsnumber still false

if ( !containsnumber ) --> value of containsnumber negated means if (true)

myarray [ count ] = number; --> myarray [ 3 ] = 4;

the value of number (4) set fourth position of array (remember, array starts 0).

now array contains values 1, 5, 7 , 4.