how to detect python, java, c programming languages using regex

detect_program_lang.md

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function trim(s){ 
  return ( s || '' ).replace( /^\s+|\s+$/g, '' ); 
}
function processData(input) {
            input = trim(input)

    var split = input.split('\n');
    split.shift();
    //regexr.com/58j2m
    var regex_java = RegExp(/(public|java|static|System|println)/);
    // regexr.com/58j16
    let regex_python = RegExp(/(print\s"?|def\s\w+:|__\w{3,4}__|None|\(self\.?|class\s\w+:\n)/)
    // regexr.com/58j2s
    let regex_c = RegExp(/(#include<.+>\n|int\smain\(\)|\/\*.+\*\/)/)
    // split.forEach(function (item) {
        if(regex_java.test(input)){
        console.log("Java");
        }else if(regex_python.test(input)){
        console.log("Python");
        }else if(regex_c.test(input)){

        console.log("C");
        }
    // });
} 

process.stdin.resume();
process.stdin.setEncoding("ascii");
_input = "";
process.stdin.on("data", function (input) {
    _input += input;
});

process.stdin.on("end", function () {
   processData(_input);
});