Can some one help me solve this logic using C#

Question

Below is the logic for what I am trying to do .Can some one help me solve this using C#.

 string strMessage=string.empty;
 for (int i = 0; i < 20; ++i)
 {
     switch i
        {
        Case 1,2,7,5:
          strMessage="You Won";
    break;
        Case 6,8,10,3:
          strMessage="You can try again";
    break;

         }

   }
Response.write(strMessage);

Whenever the value of i is 1,2,7 or 5 strMessage="You won" Whenever the value of i is 6,8,10 or 3 strMessage="You can try again"

What are you trying to do? Do you want to ask a user for input? — Matthew Whited, Nov 30 '11 at 01:04
there is no linq here... you dont need the tag... if this is homework, please add a homework tag — Muad'Dib, Nov 30 '11 at 01:07

score 7 · Answer 1 · edited Nov 30 '11 at 02:03

7

string strMessage = string.Empty;

for (int i = 0; i < 20; ++i) 
{
    switch(i)
    {
        case 1:
        case 2:
        case 7:
        case 5:
            strMessage = "You Won";
            break;
        case 6:
        case 8:
        case 10:
        case 3:
            strMessage = "You can try again";
        break;
    }
}

Response.write(strMessage);

edited Nov 30 '11 at 02:03

Marius Schulz

15,976
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answered Nov 30 '11 at 01:03

Galaxydreams

318
3
13

1

this is broken still, as another post said, it will only ever set the string to "You can try again"; – Keith Nicholas Nov 30 '11 at 02:31

score 2 · Answer 2 · answered Nov 30 '11 at 01:06

2

This particular code will always result in

strMessage = "You can try again";

because of the for loop and the fact that when i>10 the switch will not do anything.

answered Nov 30 '11 at 01:06

Emil Lundberg

7,268
6
37
53

Muad'Dib · Answer 3 · 2011-11-30T01:52:19.280

your loop will cause all the messages to be printed, as well as 12 empty lines.

here is some psuedocode for what you have:

for the values 0 to 19 
    if i == 1 or 2 or 7 or 5 then message = "You Won"
    else if i == 3 or 6 or 8 or 10 then message = "You can try again"
    else  message = string.empty

if you walk through your code in your head, or use pencil and paper your problem will become clear.

so, when it hits the largest number in you case (its 10) the message will be set to "You can try again" and will not be set again.

so, when the loop ends the message will be "You can try again"... to fix this, either move your Response.Write to be inside the loop

the syntax on your switch is all wrong:

switch (i)
{
   case 1:
   case 2:
   // do something
   break;
}

here is the MSDN reference for switch.

general guidelines are that you can have multiple case statements together, but a case CANNOT fall through (like it can in C/C++) and it has to end in a break;

Actually it'll just print out `You can try again` (Gets set on i = 10 and then not touched again) :) — Rob, Nov 30 '11 at 01:26
your right, missed the location of the Response.Write...updating my psuedocode — Muad'Dib, Nov 30 '11 at 01:50

Keith Nicholas · Accepted Answer · 2011-11-30T02:10:28.883

1

you could go with something like

public string Evaluate(int value)
{            
    if (new[] {1, 2, 7, 5}.Contains(value)) return "You Won";
    return new[] {3, 6, 8, 10 }.Contains(value) ? "Try again" : "";
}

not sure what you are trying to do with your loop... looks a bit broken, but if you are trying to write out for each 0..19

Enumerable.Range(0, 20).Select(Evaluate).ToList().ForEach(Response.write);

edited Nov 30 '11 at 02:10

answered Nov 30 '11 at 01:17

Keith Nicholas

43,549
15
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156

The downvote is probably because this code, even if its correct, and maybe looks cool, its slow compared with a simple switch/case. You create new arrays each time you call it, and then initialize it with variables, do you ever see how this is dissembled ? - and how the contains make the the final search.... ? too slow. – Aristos Sep 03 '12 at 19:26
@Aristos, always optimize last.... in this case, because the amount of cases is so small, any savings are in the "nano / microseconds" not exactly highly critical, if it got any longer, I'd maybe go to a hashlist (which is what a switch will turn into if it gets too long also). – Keith Nicholas Sep 03 '12 at 20:59
well, if you do not understand how slow is that code... I can not help more. – Aristos Sep 03 '12 at 21:31

score 0 · Answer 5 · answered Nov 30 '11 at 01:04

Each case may represent only a single value, so what you want to do is to make cases without breaks:

string strMessage=string.empty;
 for (int i = 0; i < 20; ++i)
 {
     switch i
        {
        Case 1:
        Case 2:
        Case 7:
        Case 5:
          strMessage="You Won";
    break;
        Case 6:
        Case 8:
        Case 10:
        Case 3:
          strMessage="You can try again";
    break;

         }

   }
Response.write(strMessage);

score 0 · Answer 6 · edited May 23 '17 at 12:21

I believe you are having trouble compiling this, because statements like "Case1,2,7,5" are invalid.

Instead, you need to layer them and use fallthrough/break as appropriate.

I believe this is what you are trying to achieve:

for (int i = 0; i < 20; i++)
{
    switch (i)
    {
    Case 1:
    Case 2: 
    Case 5:
    Case 7:
        strMessage="You Won";
        break;
    Case 3:
    Case 6:
    Case 8:
    Case 10:
        strMessage="You can try again";
        break;
    }

}

See relevant question Multiple Cases in Switch

score 0 · Answer 7 · answered Nov 30 '11 at 01:09

You should write like this:

string strMessage = string.Empty;
        for (int i = 0; i < 20; ++i)
        {
            switch (i)
            {
                case 1:
                case 2:
                case 7:
                case 5:
                    strMessage="You Won";
                    break;
                case 6:
                case 8:
                case 10:
                case 3:
                    strMessage="You can try again";
                    break;
            }
        }

Can some one help me solve this logic using C#

7 Answers7