C.3 The print-X-axis Function

X axis labels are much like Y axis labels, except that the ticks are on a line above the numbers. Labels should look like this:

    |   |    |    |
    1   5   10   15

The first tic is under the first column of the graph and is preceded by several blank spaces. These spaces provide room in rows above for the Y axis labels. The second, third, fourth, and subsequent ticks are all spaced equally, according to the value of X-axis-label-spacing.

The second row of the X axis consists of numbers, preceded by several blank spaces and also separated according to the value of the variable X-axis-label-spacing.

The value of the variable X-axis-label-spacing should itself be measured in units of symbol-width, since you may want to change the width of the symbols that you are using to print the body of the graph without changing the ways the graph is labeled.