C++ for-loop structure with multiple variable initialization

Question

On the 2nd for-loop, I get the following error from gcc:

error: expected unqualified-id before \'int\'

I\'m not sure what I\'m missing. I\

Answer 1

Try without the int before col.

for (int i = 0, col = 0; i < values.size(); i++, col++)

Answer 2

Others have already told you how to fix the problem you've noticed. On a rather different note, in this:

if (col > 10) { std::cout << std::endl; col == 0; }

It seems nearly certain that the last statement here: col==0; is really intended to be col=0;.

Answer 3

This should fix it

for (int i = 0, col = 0; i < values.size(); i++, col++) {
  if (col > 10) { std::cout << std::endl; col == 0; }
  std::endl << values[i] << ' ';
  }
}

A variable definition goes like this

datatype variable_name[=init_value][,variable_name[=init_value]]*;

Answer 4

This is akin to a regular multiple variables declaration/initialization in one line using a comma operator. You can do this:

int a = 1, b = 2;

declaring 2 ints. But not this:

int a = 1, int b = 2;   //ERROR

Answer 5

Don't declare int after comma use,

for (int i = 0,col = 0; i < values.size(); i++, col++) {
  if (col > 10) { std::cout << std::endl; col == 0; }
  std::endl << values[i] << ' ';
  }
}