What To Know
- The control card in a COBOL program is a file that specifies how the program is to be executed.
- For example, the “ENVIRONMENT DIVISION” section of the control card specifies the program’s input and output files, as well as other information such as the date and time it was compiled.
- The purpose of a control card in a COBOL program is to specify the runtime characteristics of the program, such as the data division, file section, working-storage section, and any input/output procedures.
If you are just starting out with COBOL programming and are wondering how to read control cards, then you’ve come to the right place! COBOL, which stands for COmmon Business-Oriented Language, is a programming language that is commonly used for a variety of business and financial applications. One of the great things about COBOL is that it is a very structured and easy-to-understand language, which makes it a great choice for beginners. In this blog post, we’ll cover the basics of how to read control cards in a COBOL program.
How To Read Control Card In Cobol Program
COBOL (Common Business-Oriented Language) is a programming language used for developing business-oriented applications. The control card in a COBOL program is a file that specifies how the program is to be executed. The control card contains information about the program, such as its name, the date and time it was compiled, and the libraries and files it uses. It also specifies the program’s input and output files, as well as any other information the program needs to run.
To interpret the control card in a COBOL program, you need to understand how the program is structured. COBOL programs are made up of sections, which are groups of statements and data that are grouped together for a specific purpose. The control card specifies which sections are to be run, in what order, and under what conditions.
For example, the “ENVIRONMENT DIVISION” section of the control card specifies the program’s input and output files, as well as other information such as the date and time it was compiled. The “PROCEDURE DIVISION” section specifies the program’s main processing steps, and the “DATA DIVISION” section specifies the program’s data elements.
To interpret the control card, you need to analyze each section and determine what it does. The control card may also contain conditions, such as “IF A > B THEN GO TO SECTION X.” These conditions are used to specify how the program is to be executed, such as which sections to run and in what order.
To read the control card in a COBOL program, you can use the following steps:
1. Analyze the sections of the control card and determine what they do.
2. Identify any conditions in the control card that specify how the program is to be executed.
3. Execute the program according to the conditions specified in the control card.
For example, if the control card specifies “IF A > B THEN GO TO SECTION X,” the program will first check the value of A and compare it to the value of B. If A is greater than B, the program will execute the statements in the “SECTION X” section. If A is not greater than B, the program will skip “SECTION X” and move on to the next section.
What Are The Components Of A Control Card In Cobol?
- 1. Data Division: Contains data items used in the program, including file sections, working storage sections, and input/output sections.
- 2. Procedure Division: Contains the program’s processing logic, including executable statements and control flow statements such as IF, PERFORM, and EVALUATE.
- 3. Environment Division: Contains information about the program’s runtime environment, such as date, time, and system-specific settings.
- 4. Data Division Initialization Section: Contains statements to initialize data items before the program begins processing.
- 5. Procedure Division Initialization Section: Contains statements to initialize the program’s processing logic before the program begins processing.
What Is The Purpose Of A Control Card In A Cobol Program?
The purpose of a control card in a COBOL program is to specify the runtime characteristics of the program, such as the data division, file section, working-storage section, and any input/output procedures. The control card contains important information that is used by the compiler and runtime system to generate and execute the program.
The data division section of the control card specifies the data files that are used by the program for input/output. The file section specifies the format and layout of the data files, including any record formats, field formats, and data item names. The working-storage section specifies any temporary data items that are used by the program, as well as any temporary files that are created for input/output.
The input/output procedures section of the control card specifies any input/output procedures that are used by the program, such as file input/output, screen input/output, and report generation. These procedures are typically written in COBOL, and are used to access and manipulate the data in the data files.
The control card also contains information about the program’s runtime environment, such as the name of the program, the name of the compiler that was used to compile the program, and any runtime options that are specified. This information can be used by the runtime system to set up the program’s execution environment, and to provide any necessary error messages or warnings.
In summary, the control card in a COBOL program specifies all of the runtime characteristics of the program, including the data division, file section, working-storage section, and input/output procedures. This information is then used by both the compiler and the runtime system to generate and execute the program.
What Is The Difference Between A Compile Time And Runtime Control Card?
Compile time (or compile time) control cards (CTCCs) are control cards that are processed when the program is compiled. They allow you to specify compiler options and settings, such as compiler flags, libraries to include, and paths to search for source files.
Runtime control cards (RTCCs) are control cards that are processed when the program is run. They allow you to specify runtime options and settings, such as environment variables, command-line arguments, and configuration files.
In summary, the main difference between a compile time control card and a run control card is when they are processed and what type of options they allow you to specify.
How Does A Compile Time Control Card Differ From A Runtime Control Card?
A compile time control card, also known as a CTC card, is a piece of hardware that is used to control the timing and sequencing of computer programs during compilation. A runtime control card, on the other hand, is a piece of hardware that is used to control the timing and sequencing of computer programs while they are running.
The primary difference between a compile time control card and a runtime control card is that the CTC card is used during the compilation process, while the runtime control card is used after the program has been compiled and is running. The CTC card is responsible for ensuring that all instructions in the program are executed in the correct order and at the right time, while the runtime control card is responsible for ensuring that all instructions in the program are executed in the correct order and at the right time.
In summary, a compile time control card is used during the compilation process, while a runtime control card is used after the program has been compiled and is running.
When Should You Use Each Type Of Control Card?
There are four types of control cards:
1. Input: Used to record data prior to a process.
2. Process: Used to record data during a process.
3. Output: Used to record data after a process.
4. Performance: Used to monitor and control a process.
You should use each type of control card for different purposes:
* Input control cards should be used to record data before a process begins. This data should be reviewed and verified to ensure that it is accurate and complete.
* Process control cards should be used to record data during a process. This data should be monitored and compared to expected results to ensure that the process is running correctly.
* Output control cards should be used to record data after a process is complete. This data should be reviewed and verified to ensure that it is accurate and complete.
* Performance control cards should be used to monitor and control a process. This data should be analyzed to identify areas for improvement and to ensure that the process is meeting its objectives.
It’s important to use each type of control card in the correct context, and to review and analyze the data collected to identify areas for improvement.
Final Thoughts
In conclusion, understanding the control card is essential in deciphering the flow of a COBOL program. By comprehending the various clauses and their relationship to each other, as well as the use of indicators and special characters, developers can gain insights into the program’s structure and logic. Armed with this knowledge, they can confidently navigate the control card and effectively troubleshoot any issues that may arise.
