Coder_Shubham_24's blog

Can someone explain this read template ?? I saw it used by many coders.....
By Coder_Shubham_24, history, 4 years ago, In English

I didn't get logic for these to lines

  1. f |= (ch == '-')
  2. x = (x << 1) + (x << 3) + (ch ^ 48);
template<class T>void read(T& x)
{
	x = 0; int f = 0; char ch = getchar();
	while (ch < '0' || ch>'9') { f |= (ch == '-'); ch = getchar(); }
	while (ch >= '0' && ch <= '9') { x = (x << 1) + (x << 3) + (ch ^ 48); ch = getchar(); }
	x = f ? -x : x;
	return;
}
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4 years ago, # |
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  1. if (ch == '-') f = true;
  2. x = x * 10 + (ch - '0');
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    4 years ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    Thanks bro it helped me

    but why they are selecting only '-'(symbol) for 1st statement if(ch =='-')f=true; might be some seprator i guess

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      4 years ago, # ^ |
        Vote: I like it +10 Vote: I do not like it

      x = f ? -x : x;

      It is to check if its a negative number.

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