What does this mean in C ++? [duplicate]

I was taking a look at how to use templates in c ++, when I come across this here return (a>b?a:b); .   ( link )
What is this ? in the code? I tried to search in google but it did not work, it seems that ? is ignored in search ...
I had seen it a few times but never cared. I believe it's some kind of formatting, just like a = a + b is equal to a+=b , right?