how to accept a carriage return ?

This is a discussion on how to accept a carriage return ? within the C Programming forums, part of the General Programming Boards category; Here is my problem... I want the user to be able to press enter and then the line of text ...

  1. #1
    Or working on it anyways mramazing's Avatar
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    how to accept a carriage return ?

    Here is my problem...

    I want the user to be able to press enter and then the line of text to repeate
    Code:
    #include <stdio.h>
    #include <stdlib.h>
    #include <string.h>
    
    int main()
    {
         char lol[20];
         while(1)
         {
              printf("command: ");
              scanf("%s", lol);
              if(strcmp(lol, "\n") == 0)
              {
                // reprint "command"
              }
          }
    }
    But... this does not work, that is my code basically. Or that is what i tried rather, I also tried "\r" but that didnt work and neither did EOF. N E ideas?
    -- Will you show me how to c++?

  2. #2
    Registered User
    Join Date
    Jan 2007
    Posts
    4
    because you are using a while loop and you have set the condition to "while(1)," it will always be true, therefore, it is unneccassary to manuelly reset it. after it prints the char "lol," it will automaticly start the while again. remember, while is a loop for a reason.

    Code:
    #include <stdio.h>
    #include <stdlib.h>
    #include <string.h>
    
    int main()
    {
         char lol[20];
         while(1)
         {
              printf("command: ");
              scanf("%s", lol);
              printf("&s\n", lol);
          }
    }
    theoreticly this should work, correct me if im wrong.

    EDIT: Sorry, didnt realize what u meant at first. this doesnt really fix your problem. im on a mac, although i believe if
    your on windows you can do...
    Code:
    #include <stdio.h>
    #include <stdlib.h>
    #include <string.h>
    
    int main()
    {
         char lol[20];
         while(1)
         {
              printf("command: ");
              scanf("%s", lol);
              printf("&s\n", lol);
              system("PAUSE");
          }
    }
    although that may be wrong. macs pwn over windows. lol.
    Last edited by PSPJunkie; 01-08-2007 at 08:52 PM.

  3. #3
    CSharpener vart's Avatar
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    Rishon LeZion, Israel
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    scanf ignores \n - it reads upto the \n and leaves \n in the input stream
    to read whole line including \n use fgets (see the FAQ about details how to read from the stdin using fgets)
    The first 90% of a project takes 90% of the time,
    the last 10% takes the other 90% of the time.

  4. #4
    Or working on it anyways mramazing's Avatar
    Join Date
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    soo fgets will accept the carriage return, right and now wait for a stream or character or something like that?

    And my example was not really the best looking back, the whole point of the example was to make so i can accept <enter> as i would a character and it would go to the next line. Like in the dos shell.
    -- Will you show me how to c++?

  5. #5
    Registered User whiteflags's Avatar
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    Maybe you meant to do something like this:
    Code:
    #include <stdio.h>
    #include <stdlib.h>
    
    int main( void )
    {
       char line[BUFSIZ];
    
       for(;;)
       {
          fputs("Please enter a string of characters.\n: ", stdout);
          fflush(stdout);
          if( fgets(line, sizeof line, stdin) != NULL  && line[0] != '\n' )
          {
             puts(line);
          }
          else if( line[0] == '\n' )
          {
             continue;
          }
          else
          {
             break;
          }
       }
    
       return 0;
    }
    Of course, now this means that the only way to stop the loop is to send EOF.

  6. #6
    Registered User ssharish2005's Avatar
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    Sep 2005
    Location
    Cambridge, UK
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    1,682
    May be this will help you

    Code:
    #include<stdio.h>
    
    int main()
    {
        char str[80];
        
        printf("Enter Command :\\>");
        
        while(fgets(str, sizeof str, stdin) != NULL && *str != '\n' && *str != EOF)
        {
            printf("Your Command > %s", str);
            printf("Enter Command :\\>");
        }    
        
        printf("You are out\n");
        
        getchar();
        return 0;
    }
    
    /* my output
    Enter Command :\>copy con hello
    Your Command > copy con hello
    Enter Command :\>dir
    Your Command > dir
    Enter Command :\>ipconfig
    Your Command > ipconfig
    Enter Command :\>
    */
    ssharish2005

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