Thread: single for loop --- two conditions??

How do you write the following as two nested loops?

Code:

for (int low = 0, high = n - 1; low < high; low++, high--)

General rule: for is only a clever way to write while loops. With your example:

Code:

for (int i = 0, j = n - 1; i < j; i++, j--)
  doSomething();

Is the same as:

Code:

/* block, because i and j are local to the loop */
{
  int i = 0, j = n - 1;

  while ( i < j )
  {
    doSomething();

    i++, j--;
  }
}

I don't think you want that as two loops, because that would change the behavior in ways you don't expect. However, you could factor the "high" variable out as a function of the "low" variable:

Code:

 
for (int low = 0; low < n / 2; ++low) {
     int high = n - 1 - low;

    // etc.
}