Modern Mainframe Development

Chapter 6. COBOL Tables and Reports

In the business world, Microsoft Excel is one of the most widely used applications. It allows for the easy creation of interactive reports that help with key decisions. The result is that Excel continues to generate huge cash flows, even though the software has been around for over 35 years.

But with COBOL on the mainframe, built-in features can help create tables and reports. Granted, they are not as sophisticated or seamless as Excel. But they are still powerful and can help run mission-critical business applications on a global basis. They have been one of the most important functions of COBOL and the mainframe computer.

In this chapter, we’ll take a look at how to use tables and reports in COBOL. We’ll also cover related topics like string manipulation.

Introduction to Tables

In a way, a COBOL table is similar to a spreadsheet. You can place numbers in certain areas, make computations, search the data, and so on. In fact, the applications are seemingly endless. You can set up a table to help compute taxes, determine the premiums for insurance, or come up with a forecast for sales.

Keep in mind that a COBOL table is the language’s version of an array. In a typical language, an array stores a string of data. And each data item is referenced with an index number. For example, let’s suppose we have an array, which we call Months, that is for the months in the year. But each has an index that starts at 0. So Months[0] is equal to January,