Added compile.php

backend/compile.php

+<?php
+
+$postData = file_get_contents("php://input");
+
+$uid = $postData['id'];
+$filename = $postData['filename'];
+$language = $postData['language'];
+
+$ret_stat = 0;
+
+if(strcmp($language, "cpp") == 0)
+{
+    $base = basename($filename, ".cpp");
+    system("g++ " . $uid . "/" . $filename . " -o " . $uid . "/" . $base , $ret_stat);
+
+    if($ret_stat != 0)
+    {
+        unlink($uid . "/" . $base);
+    }
+}
+
+else if(strcmp($language, "java") == 0)
+{
+    $base = basename($filename, ".java");
+    system("javac " . $uid . "/" . $filename , $ret_stat);
+
+    if($ret_stat != 0)
+    {
+        unlink($uid . "/" . $base . ".class");
+    }
+}
+
+echo $ret_stat;
+?>
\ No newline at end of file