Command-line arguments for Kotlin program-CodePudding

I stuck with a project. It's an encryption-decryption program. But to complicate the things it uses command-line arguments instead of user input. I solved the user input part. But this part is really hard for me. Here is the objective:

Objectives The program must parse three arguments: -mode, -key, and -data. The first argument should determine the program's mode (enc for encryption, dec for decryption). The second argument is an integer key to modify the message, and the third is a text or ciphertext to encrypt/decrypt.

Arguments are guaranteed to be passed to the program. If, for some reason, they turn out to be wrong:

If there is no -mode, the program should work in the enc mode; If there is no -key, the program should consider that it is 0; If there is no -data, the program should assume that data is an empty string. Keep in mind that the order of the arguments might be different. For example, -mode enc maybe at the end, at the beginning, or in the middle of the array.

Examples Example 1: encryption; the arguments are: -mode enc -key 5 -data "Welcome to hyperskill!"

\jqhtrj%yt%m~ujwxpnqq&

java -jar programName.jar -mode enc -key 5 -data "Welcome to hyperskill!" This way the program inputs \jqhtrj%yt%m~ujwxpnqq& But how to achieve the same input if the program starts with for example java -jar programName.jar -data "Welcome to hyperskill!" -mode enc -key 5 ?? The encoding-decoding part is done in the previous stage. Thanks in advance!

CodePudding user response：

Assuming that the command line arguments will always come in the format of -nameOfArgument and then immediately followed by the argument itself, here is a simple way. For more complicated command line options, I would recommend using a parser library like kotlinx-cli.

Because of the assumption, you will always find an even number of elements in the arguments array passed to main. You can make this array chunked into lists of 2 elements each, and then associate the two elements into a Map.

fun main(args: Array<String>) {
    val argsMap = args.toList().chunked(2).associate { it[0] to it[1] }
}

After that, argsMap["-mode"] gets you the mode, argsMap["-key"] gets you the key. These could also be null, which means that that argument is not passed.

CodePudding user response：

Fisrtly thanks to Sweeper for the assistance! Maybe not the finest solution, but here is my code:

fun main(args: Array<String>) {
    val argsMap = args.toList().chunked(2).associate { it[0] to it[1] }

    if (argsMap["-mode"] == "enc" || argsMap["-mode"] == "") {
            for (char in argsMap["-data"] ?: "") {
                    print(char   (argsMap["-key"]?.toInt() ?: "".toInt()))
            }
    } else if (argsMap["-mode"] == "dec") {
            for (char in argsMap["-data"] ?: "") {
                    print(char - (argsMap["-key"]?.toInt() ?: "".toInt()))
            }
    } else if (argsMap["-key"] == "") {
            print(argsMap["-data"])
    } else if (argsMap["-data"] == "") {
            print("")
    }

}