For loop

Question

is it necessary to put values in all three fields i.e init,condition and increment in for loop?

Answer 1

no, but then the loop will run continuously

Answer 2

no, a semi colon serves to distinguish what you mean. Obviously the condition must evaluate true

for(;1==1;) cout<<"1";
//is an infinite loop.

To have more than one increment operation, use a coma to separate each.

for(int i = 0; i <= 5; ++i,++j);

notice there is no body, in many cases it can all be inside the original parenthesise.

Answer 3

@S!d:

But you can do:

int i=5;
for (;;) {
cout << "Hi" << endl;
i--;
if (i==0) break;
}

( don't ask me why, apart to prove that you can, without running infinitly :D )

Answer 4

not all three fields , but any 2 or 1field