EXAMPLE
What is the simplest way to print a text bar chart? Look at these two versions for input 3, 2, 5, 1
Version 1
Version 2
*
***
*
**
* *
*****
***
*
****
Issues to consider:
Reading in the input data set
o
What would be easiest for a user? Input text file? Keyboard input? One-line input?
The control structure (algorithm)
o
The fewer loops and ifs the better. The least convoluted the better.
The ease of testing (validation)
o
What would be easiest for testing? Text file? Keyboard? File redirection? Other?
What would be the optimal compromise?
Algorithm for version 1 output:
Algorithm for version 2 output:
// assume int array[] = {3,2,5,1};
// assume int array[] = {3,2,5,1};
for(i=0; i<array.length; i++) {
max=0;
for(j=0; j<array[i]; j++) printf(“*”);
for(i=0; i<array.length; i++) if (array[i]>max) max=array[i];
println();
for(i=0; i<array.length; i++, max–)
}
for(j=0; j<array.length; j++) {
if (array[j]>=max) printf(“*”);
else printf(“ “);
}
Notice that in the above algorithms to print the vertical bar chart we must also print blank spaces. For example, the bar
of 5 stars is in the third column. We need to print spaces for the first two columns before printing the top star. The
version 2 output requires us to think in a 2D grid. The version 1 algorithm does not have this 2D grid requirement. We
can simply print starts horizontally and then go to the next line of stars. When looking at the sample pseudo-code, we
can see that version 1 is easier to understand, and shorter.
Unless there is a requirement by the product owner that they want a vertical bar chart, then version 1 would be the
simplest to develop, understand, maintain, write documentation and test.
PROBLEM 1
In the “Issues to consider” section of the example there are two items that are dependent on each other: “Reading in
the input data set” and “The ease of testing”. They are related because they both deal with giving the program a data
set. In one case the user is providing the real data set, and in the second case the developer is providing many test data
sets to validate the algorithm. A good program makes it easy to do both. The use-case is however different. The user
will probably want to input only 1 or 2 data sets. The developer will want to input 100 data sets. The order of
magnitude is different.
What would be the simplest way that ensures ease of use and correctness?
PROBLEM 2
Write the complete optimal program using a professional writing style.