COBOL, or Common Business Oriented Language, is a programming language that has been around since the 1950s. Despite its age, it is still widely used in the business world for its ability to handle large-scale data processing. One of the challenges that COBOL programmers face is concatenating unknown-length strings. In this article, we will explore the various techniques and strategies for concatenating unknown-length strings in COBOL.
First, let's define what concatenation means. Concatenation is the process of combining two or more strings to form a single string. In COBOL, strings are stored as character data and can be of varying lengths. Unlike other programming languages, COBOL does not have built-in functions for string manipulation. Therefore, concatenating unknown-length strings in COBOL requires a bit of creativity.
One of the methods for concatenating unknown-length strings in COBOL is by using the STRING statement. This statement allows you to concatenate strings with a known maximum length. For example, if you have two strings, STR1 and STR2, and you want to concatenate them into a new string, STR3, you would use the following code:
STRING STR1(1:10) STR2(1:15) INTO STR3(1:25)
In this example, we are concatenating STR1 and STR2 into STR3, which has a maximum length of 25 characters. The (1:10) and (1:15) indicate the starting position and length of the strings to be concatenated. This method works well when the maximum length of the resulting string is known. However, when dealing with unknown-length strings, this approach may not be feasible.
Another method for concatenating unknown-length strings is by using the INSPECT statement. This statement allows you to search for a specific character or string within a string and replace it with another string. For example, if you have two strings, STR1 and STR2, and you want to concatenate them into a new string, STR3, you could use the following code:
INSPECT STR3 TALLYING WS-COUNT FOR ALL SPACES
INSPECT STR3 REPLACING ALL SPACE BY STR1
INSPECT STR3 TALLYING WS-COUNT FOR ALL SPACES
INSPECT STR3 REPLACING ALL SPACE BY STR2
In this example, we are using the INSPECT statement to replace all spaces in STR3 with STR1 and then STR2. This method works well when the strings to be concatenated do not contain spaces. However, if there are spaces in the strings, this approach may not produce the desired result.
A more flexible method for concatenating unknown-length strings is by using the UNSTRING statement. This statement allows you to break a string into multiple parts and store them in different variables. For example, if you have a string, STR1, and you want to concatenate it with another string, STR2, you could use the following code:
UNSTRING STR1 DELIMITED BY SPACE INTO WS-STR1-1, WS-STR1-2, WS-STR1-3
UNSTRING STR2 DELIMITED BY SPACE INTO WS-STR2-1, WS-STR2-2, WS-STR2-3
STRING WS-STR1-1 WS-STR2-1 DELIMITED BY SPACE INTO WS-RESULT
STRING WS-STR1-2 WS-STR2-2 DELIMITED BY SPACE INTO WS-RESULT
STRING WS-STR1-3 WS-STR2-3 DELIMITED BY SPACE INTO WS-RESULT
In this example, we are using the UNSTRING statement to break STR1 and STR2 into three parts each and then concatenating them into a new string, WS-RESULT. This method is useful when dealing with strings of varying lengths and allows for more flexibility in the concatenation process.
In conclusion, concatenating unknown-length strings in COBOL can be challenging, but there are various techniques and strategies that can be used to overcome this challenge. The STRING, INSPECT, and UNSTRING statements are some of the methods that COBOL programmers can use to concatenate strings of varying lengths. By understanding these techniques, COBOL programmers can efficiently handle unknown-length strings in their programs.
