Can not understand working of a line

Question

I took few help online to complete my task. And I found this code but I do not know the actual working as I have never used such syntax before in c++. The (?) Question mark and (:) colon.Can any one provide a simple general syntax code explaining same line?

x = (i-coins[j] >= 0)? table[i - coins[j]][j]: 0;

(The Conditional (or Ternary) Operator)[http://www.cplusplus.com/articles/1AUq5Di1/ ] " The ?: operator returns one of two values depending on the result of an expression. : " — Mara Black, Dec 17 '16 at 16:16
If searching the web for smth. like *"c++ what does the question mark mean"* did not lead you to an answer you need a better search engine. — Baum mit Augen, Dec 17 '16 at 16:18

score 2 · Answer 1 · answered Dec 17 '16 at 16:11

2

This means

if (i-coins[j] >= 0)
    x = table[i - coins[j]][j];
else
    x = 0;

answered Dec 17 '16 at 16:11

meedz

132
13

score 0 · Answer 2 · answered Dec 17 '16 at 16:13

This is called ternary operator, and it is used in place for a short if-else statement.

int factorial(int number) {
  if (number < 1) {
    return 1;
  } else {
    return number*(number-1);
  }
}

The above function can be summed up using a ternary operator:

int factorial(int number) {
  return (number < 1) ? 1 : number*(number-1);
}

Can not understand working of a line

2 Answers2