How To Think Like a Computer Scientist C++ Edition The Pretext Interactive Version

A two-dimensional table is a table where you choose a row and a column and read the value at the intersection. A multiplication table is a good example. Let’s say you wanted to print a multiplication table for the values from 1 to 6.

A good way to start is to write a simple loop that prints the multiples of 2, all on one line.

The first line initializes a variable named i, which is going to act as a counter, or loop variable. As the loop executes, the value of i increases from 1 to 6, and then when i is 7, the loop terminates. Each time through the loop, we print the value 2*i followed by three spaces. By omitting the endl from the first output statement, we get all the output on a single line.

The output of this program is:

2   4   6   8   10   12

So far, so good. The next step is to encapsulate and generalize.

#include <iostream>
using namespace std;

int main() {
  int x = 1;
  while (x <= 6) {
    cout << 3 * x << "   ";
    x = x + 1;
  }
  cout << endl;
  return 0;
}

#include <iostream>
using namespace std;

int main() {
  int x = 1;
  while (x <= 6) {
    cout << 3 * x << "  ";
    x = x + 1;
  }
  cout << endl;
  return 0;
}