From COBOL to OOP
Written for the experienced COBOL programmer, this nuts and bolts guide offers a comprehensive introduction to OOP techniques, and provides a migration of 10 million lines of COBOL code to object-oriented programming.
TABLE OF CONTENTS From COBOL to OOP
3.2: Replacement for the Procedure Division: Instructions
3.2 Replacement for the Procedure Division: Instructions
There are no divisions in OOP
As mentioned, there is no counterpart of the COBOL's "division" in object-oriented programming. On the other hand, object-oriented programming divides programs into several parts (although the division is less strict). The instruction part discussed in this section corresponds roughly to the Procedure Division. In particular, this section introduces the most important instructions: value assignment, branch instructions, and loops.
3.2.1 Assigning Values
Although COBOL uses three different types to assign one value to another MOVE, COMPUTE, and SET object-oriented programming has only one assignment operator. It does not matter whether the new value is a constant or an expression yet to be computed.
Delphi
In Delphi, the assignment operator is :=.
Java
In Java, the assignment operator is =.
Basically, a value assignment of the type x := y means that the left side is evaluated first (naturally in this case, but it could well be a value that would have to be determined first, for example, the xth element of an array). The right side is evaluated next, and finally, the value of the left side is replaced by the value of the right side. A (composite) variable must be on the left, and both sides must be compatible in terms of assignment.
Compatibility in terms of assignment or type does not necessarily mean that both variables have to be of the same type. We also speak of type compatibility when the...
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