Error in sending/receiving strings while using sendto() and recvfrom()

ferenczi · 11-27-2008, 04:36 PM

Hello!

I have the following problem:
My Client waits for a string and sends it to a Server:

Code:

memset(&echoString2, 0, sizeof(echoString2));

    fprintf(stdout,"\nInput a string: ");

    do {
		fscanf(stdout, "%s", echoString2);
		} while (strlen(echoString) > MAX);

    echoStringLen = strlen(echoString2);

    if (sendto(sock, echoString2, echoStringLen, 0, (struct sockaddr *)
                   &echoServAddr, sizeof(echoServAddr)) != echoStringLen)
            printError("\nError in sendto().");

The Server receives this string and counts vowels:

Code:

memset(&echoBuffer, 0, sizeof(echoBuffer));

        if ((recvMsgSize = recvfrom(sock, echoBuffer, MAX, 0,
            (struct sockaddr *) &echoClntAddr, &cliAddrLen)) < 0)
            printError("\nrecvfrom() failed.");

        fprintf(stdout, "Received string: %s", echoBuffer);

        for (i = 0; i < strlen(echoBuffer); i++)
        {
        	switch(echoBuffer[i]) {
				 case 'a': k++; break;
				 case 'A': k++; break;
				 case 'e': k++; break;
				 case 'E': k++; break;
				 case 'i': k++; break;
				 case 'I': k++; break;
				 case 'o': k++; break;
				 case 'O': k++; break;
				 case 'u': k++; break;
				 case 'U': k++; break;
        	}
        }

But I've noted, when I send a a string with blanks, the receivfrom() stops to the first word and counts the vowels of this one. I don't know why. Any idea?

PS: I use Eclipse on Win.

tabstop · 11-27-2008, 04:58 PM

fscanf with %s cannot read a string with spaces in it. If you want to read a string with spaces in it, fscanf is not for you; maybe use fgets instead.

(And do you really intend to read from stdout?)

matsp · 11-27-2008, 05:15 PM

Not that it makes any difference to the question you are asking, but did you know that:

Code:

				 case 'a': k++; break;
				 case 'A': k++; break;
				 case 'e': k++; break;
				 case 'E': k++; break;
				 case 'i': k++; break;
				 case 'I': k++; break;
				 case 'o': k++; break;
				 case 'O': k++; break;
				 case 'u': k++; break;
				 case 'U': k++; break;

can be written as:

Code:

				 case 'a': 
				 case 'A': 
				 case 'e': 
				 case 'E': 
				 case 'i': 
				 case 'I': 
				 case 'o': 
				 case 'O': 
				 case 'u': 
				 case 'U': k++; break;

(Sorry, but I'm quite allergic to repeated code).

--
Mats

ferenczi · 11-28-2008, 12:12 AM

@tabstop: fscan with stdout is a typing error (thanks for telling me). I've used fgets() and works fine (thanks).
@matsp: thank you for your tip about writing code: I've corrected the switch.

11-27-2008, 04:58 PM	#2
tabstop and the Hat of Guessing Join Date: Nov 2007 Posts: 8,740	fscanf with %s cannot read a string with spaces in it. If you want to read a string with spaces in it, fscanf is not for you; maybe use fgets instead. (And do you really intend to read from stdout?)
tabstop is offline

11-27-2008, 05:15 PM	#3
matsp Kernel hacker Join Date: Jul 2007 Location: Farncombe, Surrey, England Posts: 15,686	Not that it makes any difference to the question you are asking, but did you know that: Code: case 'a': k++; break; case 'A': k++; break; case 'e': k++; break; case 'E': k++; break; case 'i': k++; break; case 'I': k++; break; case 'o': k++; break; case 'O': k++; break; case 'u': k++; break; case 'U': k++; break; can be written as: Code: case 'a': case 'A': case 'e': case 'E': case 'i': case 'I': case 'o': case 'O': case 'u': case 'U': k++; break; (Sorry, but I'm quite allergic to repeated code). -- Mats __________________ Compilers can produce warnings - make the compiler programmers happy: Use them! Please don't PM me for help - and no, I don't do help over instant messengers.
matsp is offline

11-28-2008, 12:12 AM	#4
ferenczi Registered User Join Date: Feb 2008 Posts: 17	! @tabstop: fscan with stdout is a typing error (thanks for telling me). I've used fgets() and works fine (thanks). @matsp: thank you for your tip about writing code: I've corrected the switch.
ferenczi is offline

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