Description
Implement a C++ program that is explained below using UNIX operating system.
In this Lab, we want you to implement a multi-threaded program that creates a file and performs a word (sub-string) search and count program. First your program will need to create multiple threads whose tasks are threefold.
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Create a file
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Write the file (fill in the file with random letters without blanks)
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Search and count the given sub-strings.
Detailed Explanation of Tasks
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Create a file
Your program should create an empty file by a thread. Name the file as “big.txt”.
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Write the file
Your program should fill in the file by a thread with random letters. The letters can be lower or upper case ([a-zA-Z]). Your file must be filled with 250.000.000 letters that are concatenated to each other.
Example of file content
“…..
lfnqopSrehglaKQIAksdlfkahQWMNsldfkqMerhPQIBMAqnlgkaIASEGKCXJavjqovAJGi
KnvhajwIGJahgIqAVHBqhvahsJqbJZubENguaOSasdiQNvuasJhasqHMNKzorBJAaarEbh
…..”
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Search and count the given sub-strings
Your thread/s should search for 5 sub-strings with different sizes. The sub-strings you are responsible to find are;
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x
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os
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cpu
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disk
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cache
However, your search shouldn’t be case sensitive. If a sub-string “os/OS/Os/oS” is found, you should increment the sub-string count for “os”.
Run your program with different numbers of threads and how many of the threads are responsible of a specific task. Running your program with only “n” number of threads will not gain you points.
Prepare a report containing a table that shows the execution time of each configuration (how many threads are used for tasks). And your comments on the results.
And answers to these questions;
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What is the optimal number of threads for your computer? Why do you think it is the optimal number?
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When the use of threads does become necessary or unnecessary? Why? Explain your answer.
