Why is my c# code not working? -

i have made console program in c# to-do task manager.
not work when code reached:

using system; using system.collections.generic; using system.io; using system.linq; using system.text; using system.threading.tasks;  namespace to_do_list { class program {     static void main(string[] args)     {         string path = @"c:\todotask.txt";         console.writeline("to-do program");         while (true)         {             if (console.readline() == "exit")             {                 environment.exit(0);             }              if (console.readline() == "add")             {                 console.writeline("please write task , press enter");                 string task = console.readline();                 console.writeline("task added");                 try                 {                     streamwriter sw = new streamwriter(path);                     sw.writeline(task);                 }                 catch                 {                     console.foregroundcolor = consolecolor.red;                     console.writeline("error: not write task file");                     console.resetcolor();                 }             }              if (console.readline() == "show")             {                 try                 {                     console.writeline("tasks:");                     streamreader sr = new streamreader(path);                     if (sr.readtoend() != "")                     {                         console.writeline(sr.readtoend());                     }                     else                     {                         console.writeline("no tasks left");                     }                 }                 catch                 {                     console.foregroundcolor = consolecolor.red;                     console.writeline("error: not read tasks file");                     console.resetcolor();                 }             }              if (console.readline() == "help")             {                 console.writeline("write 'add' add new task");                 console.writeline("write 'show' see current tasks");                 console.writeline("write 'exit' exit program");             }         }       }     } } 

i new programming , can't find error. when write add, show or exit, or nothing happens. thanks.

one problem keep calling console.readline() every comparison. means you're checking a new input user every time.

instead, need call console.readline() once, store result in variable, , compare against of possible matches. also, using switch statement make code simpler.

while (true) {     var input = console.readline();      switch (input)     {         case "exit":             environment.exit(0);             break;          case "add":             // ...             break;          // ...          default:             console.writeline("invalid input");             break;     } }