I don't understand arrays and loops

Question

please help me

Answer 1

For the line a[j]+=j:
This is equivalent to writing a[j] = a[j] + j

So when j = 2, a[2] = 5 and so a[2] = 5 + 2 = 7.

Hope this helped.

Answer 2

var a = [3,8,5];
for(var j = 0;j<3;j++) {
a[j]+=j;
}
document.write(a[2]);
Ans=7.But how?

Answer 3

where do u face problem ?

Answer 4

how j=2?

Answer 5

j= 2 because in an array you start at 0. for example : a[0]=3 a[1]=8 and a[2] = 5. so you do the loop and the last loop is j= 2 and a[j] ==a[2]. so a[j] +=j gives 5+2 --> 7

Answer 6

before loop executes

a[0]=3
a[1]=8
a[2]=5

a[j]+= j;
a[j] =a[j] + j

j= 0

sum of 0th array element and value if j =0
a[0] = 5 + 0;
= 5
sum of a[1] array element and value of j=1
secon time loop:
j = 1;
a[1] = 8 +1;
= 9
sum of a[2] array element and j = 2
third time loop;:
j = 2;

a[2] = 5 + 2;
= 7;

loop ends here as loop end of condition j< 3 matches.

Answer 7

Thanks all for answer.

Answer 8

Arrey is collection of many values.. and loop is a way to exucute a function many time as u want.

Answer 9

in ur code u got anser 7 becouse u get 2 from your loop and then u add 2 of 3rd value of Array (a) and third value of (a) array is 5 so 5+2=7

Answer 10

Array is used to contain many elements of the same type, so the size can be less and program will be easier to understand.
while loop are used for repetition ,. such as if you want to print nos from 1 to 10 , then we have write 10 statements which is not the way of coding , but through loop we can write in simple and coding way:
for(i=1;i<=10;i++)