C Board http://cboard.cprogramming.com en Fri, 20 Nov 2009 21:43:53 GMT vBulletin 60 http://cboard.cprogramming.com/images/misc/rss.jpg C Board http://cboard.cprogramming.com simulating alt+2 (keypad) combination http://cboard.cprogramming.com/cplusplus-programming/121812-simulating-altplus2-keypad-combination.html Fri, 20 Nov 2009 21:02:16 GMT I am trying to print the corresponding Unicode character for alt+2 to the Windows console window. (the console doesn't display the character, but should display ^B instead)
The following doesn't seem to work. Just prints "2".

Code:
keybd_event(VK_MENU,0 ,0 , 0); //Alt Press

Sleep(10);
keybd_event(VK_NUMPAD2,0, 0 , 0); // 2 Press

Sleep(10);
keybd_event(VK_NUMPAD2,0, KEYEVENTF_KEYUP,0); // 2 Release

Sleep(10);
keybd_event(VK_MENU,0,KEYEVENTF_KEYUP,0); // Alt Release

Sleep(10);
Neither does this work. Just prints "2", again.

Code:
INPUT inputs = {0};
        inputs.type = INPUT_KEYBOARD;

        KEYBDINPUT ki = {0};
        ki.wVk = VK_LMENU;

        inputs.ki = ki;
        SendInput(1, &inputs, sizeof(INPUT)); // Left alt

        ki.wVk = VK_NUMPAD2;
        inputs.ki = ki;
        SendInput(1, &inputs, sizeof(INPUT)); // Numpad 2

        ki.dwFlags = KEYEVENTF_KEYUP;

        ki.wVk = VK_NUMPAD2;
        inputs.ki = ki;
        SendInput(1, &inputs, sizeof(INPUT)); // Numpad 2

        ki.wVk = VK_LMENU;
        inputs.ki = ki;
        SendInput(1, &inputs, sizeof(INPUT)); // Left alt
]]> C++ Programming kangekraam http://cboard.cprogramming.com/cplusplus-programming/121812-simulating-altplus2-keypad-combination.html Question about reading in strings and integers http://cboard.cprogramming.com/c-programming/121811-question-about-reading-strings-integers.html Fri, 20 Nov 2009 20:56:34 GMT Hi, I am reading in strings and integers and I am wondering, am I doing this correctly where I will prevent overflow problems and also not have a bunch of issues with my strings? Since I started messing with C, I have had tremendous problems getting this stuff to work and I think I got it now. I... Hi,

I am reading in strings and integers and I am wondering, am I doing this correctly where I will prevent overflow problems and also not have a bunch of issues with my strings? Since I started messing with C, I have had tremendous problems getting this stuff to work and I think I got it now. I am just wondering how to improve the code I wrote.

Code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>

void read(char *out, const int size);
int readint(int *out);
void readdouble(double *out);

int main(void)
{
        char buffer[17] = {0};
        int i = 0;
        double d = 0;

        printf("read string[16]: ");
        read(buffer, 17);

        printf("read integer: ");
        if(!readint(&i)) {
                printf("the number you entered is beyond the range allowable, please try again.");
                while(!readint(&i)) {
                        printf("the number you entered is beyond the range allowable, please try again.");
                }
        }
       
        printf("read: %s\t\t%d\n\n", buffer, strlen(buffer));
        printf("readint: %d\n\n", i);
        printf("readint: %5.2f\n\n", d);
       
        system("PAUSE");
        return 0;
}

/**
        function:      read
        purpose:        reads in a string and assigns it to out. Requires a length of
                                string parameter of n+1 (+1 allows for null terminator).
        args:          char *out, const int strlen
        returns:        void
*/
void read(char *out, const int strlen)
{
        char ch;
        int char_count = 0;

        // Read in the keyboard input until enter is pressed or
        // we exceed the buffer. We will not allow the buffer
        // to overflow by restricting what actually gets written
        // to the pointer.
        ch = getchar();
        *(out)++ = ch;

        while(ch != '\n' && ++char_count < strlen-1) {
                ch = getchar();
                if(char_count < strlen-1)
                        *(out)++ = ch;
        }
        // Null terminate the pointer so it is a proper string
        *out = '\0';
        // Flush the remaining keyboard input
        fflush(stdin);
}

/**
        function:      readint
        purpose:        reads an integer and assigns it to the out pointer parameter.
        defines:        INT_LEN
        args:          int *out
        returns:        int (1 success, -1 error)
*/
#define INT_LEN 100
int readint(int *out)
{
        char buf[INT_LEN];              /* buffer for retriving an int */
        char tmpbuf[INT_LEN];  /* temporary buffer for reconverting the int to a string to check for integer overflow */
        int i, tmpbuflen, buflen;

        read(buf, INT_LEN);            /* read input from the user as a string */
        i = atoi(buf);                  /* convert the string to an int */

        // Reconvert to a string to ensure that the conversion didn't cause an integer overflow
        itoa(i, tmpbuf, 10);
        tmpbuflen = strlen(tmpbuf);
        buflen = strlen(buf) - 1; /* subtract 1 for the null terminator, otherwise comparison will fail */

        if(tmpbuflen != buflen || INT_MIN < i && i > INT_MAX) // check if they are the same and within signed integer ranges
                return 0;
       
        *out = i;
        return 1;
}
]]> C Programming sgalland http://cboard.cprogramming.com/c-programming/121811-question-about-reading-strings-integers.html Array size set by variable http://cboard.cprogramming.com/c-programming/121810-array-size-set-variable.html Fri, 20 Nov 2009 20:49:25 GMT Hi,

I am having issues compiling a program with cc on a fairly old unix system, I understand that I need to follow C standards strictly but I can find no way around this.
Code:
array(int n)
{
int i;
int array[n];

for(i=0;i<=n-1;i++)
        {
        array[i]=i+1;
        }
        exit(0);
}
It is a simple function to setup an array to size n which is collected and passed in from the main function. The compiler is freaking at the array declaration, saying that I have declared an array of 0 and that the expression is not constant, as it compiles line by line and this is the last function I am happy with the rest of my code.
Does anyone have any ideas how I can get around this?

Thanks ]]> C Programming Drainy http://cboard.cprogramming.com/c-programming/121810-array-size-set-variable.html Problem with shared memory http://cboard.cprogramming.com/c-programming/121809-problem-shared-memory.html Fri, 20 Nov 2009 20:40:44 GMT Hi everyone, I have this problem. Code: --------- ......... ......... open shared memory..... Hi everyone,

I have this problem.

Code:
.........
.........
open shared memory.....
.........       
        sem_init(&mutex, 0, 1);
        sem_trywait(&mutex);

        int i=0;
        while (i<n) {
            int f = fork();
            if (f==0) {
                RSA *rsa;
                rsa = RSA_generate_key(1024 , 65537, NULL, NULL);
                ptr[i].a=BN_bn2hex(rsa->d);
                ptr[i].b=BN_bn2hex(rsa->n);
                exit(0);
                  }
                i++;
        }
sem_post(&mutex);


sem_wait(&mutex);

int z=0;
while(z<n)
{
printf("%s\n",ptr[z].a);
printf("%s\n",ptr[z].b);
z++;
}
.........
close shared memory......
.........
.........
when i do printf(ptr[z].a) or printf(ptr[z].b) i don't receive the BN_bn2hex(rsa->d), but Segmentation Fault.

Any sugestion to solve this......
Thanks. ]]> C Programming dimaneg http://cboard.cprogramming.com/c-programming/121809-problem-shared-memory.html String testing http://cboard.cprogramming.com/c-programming/121808-string-testing.html Fri, 20 Nov 2009 20:32:26 GMT Hello, im trying to design a function that takes in a string, and test it for having

" The first 1/3 (rounding down) of the word's letters is repeated elsewhere in the word. e.g. abracadabra"

I understand the logic of looping through the array, and finding matches, but have been un-able to create a working test that does the above task correctly.

and help would be greatly appreciated.

thanks
nailz ]]> C Programming Nailz http://cboard.cprogramming.com/c-programming/121808-string-testing.html Arrays and Functions http://cboard.cprogramming.com/cplusplus-programming/121807-arrays-functions.html Fri, 20 Nov 2009 20:02:57 GMT Hello,

I have created a simple program that will be adding data into a file, but I need to get this part going first. I'm having a problem when trying to add the name of the item. It skips that line and jumps to the next one not letting me to enter the name. Any help on this will be appreciated.

Code:
#include <iostream>
#include <iomanip>
#include <fstream>
#include <cctype>

#define cMax 100

using namespace std;

void invMenu();
void crtNewItem(double Qty[], double iPrice[], char iName[], int pNumber[]);

int main()
{
    int mSelec;
    bool bDone = false;

        do{

cout << "1. Inventory Management" << endl;
cout << "\nPlease enter your selection [1-5]" << endl;
cin >> mSelec;
while (mSelec < 1  || mSelec > 5)
{
        cout << "Please enter a correct selection between 1-5" << endl;
        cin >> mSelec;
}

switch(mSelec)
{
  case 1: invMenu();
  break;

  }
}while (!bDone);
return 0;

}

void invMenu()

 {
    double Qty[cMax];
    double iPrice[cMax];
    char iName[cMax];
    int pNumber[cMax];

    int iSelec = 0;
        system("cls");

cout << "\n1. Create New Item" << endl;
cout << "\nPlease enter your selection [1-6]" << endl;
cin >> iSelec;
while (iSelec < 1  || iSelec > 6)
{
        cout << "Please enter a correct selection. [1-6]" << endl;
        cin >> iSelec;
}

switch(iSelec)
{
    case 1:
                //This calls out the fuction to create a new item.
                crtNewItem(Qty,iPrice,iName,pNumber);
    break;
}

 }

void crtNewItem(double Qty[], double iPrice[], char iName[], int pNumber[])

{
        system("cls");
        ofstream outputFile;

 outputFile.open("InvItems.txt", ios::app);

                                cout << "Please enter the quantity of the item:__";
                                        cin >> Qty[cMax];

                                cout << "Please enter the name of the item:__";
                    cin.getline(iName, cMax);

                cout << "Please enter the part number of the item:__";
                    cin >> pNumber[cMax];

                                cout << "Please enter the price of the item:__";
                    cin >> iPrice[cMax];

                outputFile << Qty[cMax] << setw(10) << iName[cMax] << setw(10) << pNumber[cMax] << setw(10) << iPrice[cMax] << endl;
                outputFile.close();


                    cout << "\n************************************************";
                                cout << "\nYou have just added a new item to the inventory!";
                    cout << "\n************************************************" << endl << endl;
}
Any advice on how to solve this will be appreciated. Thanks! ]]> C++ Programming drkidd22 http://cboard.cprogramming.com/cplusplus-programming/121807-arrays-functions.html CPU increase with precomputed tables? http://cboard.cprogramming.com/cplusplus-programming/121806-cpu-increase-precomputed-tables.html Fri, 20 Nov 2009 19:44:58 GMT (edit: I'm done editing now, I promise. Maybe.)

The problem is that using precomputed tables results in higher CPU usage and that's confusing me. The routine which creates the table is in fact occurring outside of the applications render loop. It is NOT being recomputed every iteration.

So here are the details;

I've designed a class which executes some numerical algorithms and I've added some methods which allow user to specify the location to some precomputed tables to speed things up.

Code:
vector< vector< float > > *TCOS, *TSIN;
//...
void ALG::UseTrigTables(vector< vector< float > > *fsin, vector< vector< float > > *fcos)
{
        TCOS = fcos;
        TSIN = fsin;
}
After the object is created I will attach the tables like so;

Code:
vector< vector< float > >
 tcos(N, vector< float > (N)),
 tsin(N, vector< float > (N));

// [insert loop here to fill vector-vectors with data]... etc...

Blah.UseTrigTables(&fsin, &fcos)
Within the class the tables are used like so;

Code:
float f0;
for (int k = 0; k < N; ++k)
for (int j = 0; j < N; ++j)
{
        f0 = fA[k] * fB[j] * (*TSIN)[k][j];
        // ...
}
Why would that increase CPU usage?

With trig: ~8%
With tables: ~10%

Where N = 128 (size of tables/loop)

My first guess;

While I am passing a pointer, maybe I'm missing something critical and the tables are actually being copied to a new location in memory every time i call them??

If not, what exact tools do you recommend I use to profile this applications behavior? ]]> C++ Programming since http://cboard.cprogramming.com/cplusplus-programming/121806-cpu-increase-precomputed-tables.html Counting Pixels In A Blob http://cboard.cprogramming.com/c-programming/121805-counting-pixels-blob.html Fri, 20 Nov 2009 19:44:17 GMT The purpose of the program is to take a position and count how many "pixels" are in the "blob". If there is no "pixel" aka the value is 0, the blob number is 0. If there is a pixel, the blob_check function recursively checks the surrounding cells for "pixels" aka values of 1. My program compiles but doesn't accurately count the number of pixels in the blob. If I ask it to count the number of pixels in the blob for (0,0) it gives a 4 instead of a 5. Please help!



Code:
#include <stdlib.h>
#include <stdio.h>

#define N 5

int blob_check(int pic[N][N], int x, int y)
{
        if (pic[x][y] == 0)
                return 0;
        else
        {
                pic[x][y] = 0;
               
                int sum = 1;
               
                //check
                if (x>0)
                {
                        sum += blob_check(pic, x-1, y);
                        if (y<N-1)
                                sum += blob_check(pic, x-1, y+1);
                }
                else if (y<N-1)
                {
                        sum += blob_check(pic, x, y+1);
                        if (x<N-1)
                                sum += blob_check(pic, x+1, y+1);
                }
                else if (x<N-1)
                {
                        sum += blob_check(pic, x+1, y);
                        if (y>0)
                                sum += blob_check(pic, x+1, y-1);
                }               
                else if (y>0)
                {
                        sum += blob_check(pic, x, y-1);
                        if (x>0)
                                sum += blob_check(pic, x-1, y-1);
                }

                return sum;
        }
}

int main()
{
        int x,y,i,j;
        int row=0;
        char line[80];
        int table[N][N] = { {1,1,0,0,0},
                                                {0,1,1,0,0},
                                                {0,0,1,0,1},
                                                {1,0,0,0,1},
                                                {0,1,0,1,1}};
                               
        printf("\t0\t1\t2\t3\t4\t");
        printf("\n  -----------------------------------------");                       
        for(i=0;i<5;i++)
        {
                printf("\n  |\n%d  |\t", i);
                for(j=0;j<5;j++)
                {
                        printf("%d\t", table[i][j]);
                }
        }
                                                               
                                                               
        printf("\n\nEnter x-y coordinates of cell  => ");
        scanf("%d %d", &y, &x);                                                               
       
        printf("Pixel quantity in blob: %i\n", blob_check(table, x, y));
       
        system("pause");
        return 0;
}
]]> C Programming cokacola http://cboard.cprogramming.com/c-programming/121805-counting-pixels-blob.html String with two words: 1)String, 2) $double http://cboard.cprogramming.com/c-programming/121804-string-two-words-1-string-2-%24double.html Fri, 20 Nov 2009 19:10:05 GMT I have a string saved in memory with exactly one space in the middle and two substrings; the string is formatted like this:

"Mike $120.00"

The first word will be saved as a string, the second needs to be converted to a float. Please, how can I do separate this string at the space and convert the 2nd string into a float?

Thanks in advance. ]]> C Programming Roger http://cboard.cprogramming.com/c-programming/121804-string-two-words-1-string-2-%24double.html help http://cboard.cprogramming.com/tech-board/121803-help.html Fri, 20 Nov 2009 18:33:22 GMT just 1na 2 know if I can I install 2003 visual studio.net on windows vista and if work..? ty all... just 1na 2 know if I can I install 2003 visual studio.net on windows vista and if work..?
ty all... ]]> Tech Board Carzon http://cboard.cprogramming.com/tech-board/121803-help.html Basic operator overloading question http://cboard.cprogramming.com/cplusplus-programming/121802-basic-operator-overloading-question.html Fri, 20 Nov 2009 18:04:22 GMT Hi there,

I'm just starting to try out Operator Overloading and wrote a basic definition for the equality operator ==.

base.h :
Code:
class Base
{
public:
        Base (int a);
        int getNo() const { return m_a; }

private:
        int m_a;
};
Base::Base(int a)
{
        m_a = a;

}
bool operator==(const Base& leftparameter, const  Base& rightparameter)
{
        leftparameter.getNo() == rightparameter.getNo();
        return true;
}

main.cpp :
Code:
#include <iostream>
#include "base.h"

using namespace std;

int main()
{
        Base obj1(1);
        Base obj2(1);

        if(obj1 == obj2)
        {
                cout << "Objects match" << endl;
        }
        else
        {
                cout << "Objects don't match" << endl;
        }
        system ("pause");
        return 0;
}
Just a basic query, Visual Studio reports:

Quote:
warning C4553: '==' : operator has no effect; did you intend '='?
I'm just wondering why it says == has no effect when it does successfully compare the two objects.
I don't see why would it think I meant to assign one object to another.

Should I not worry about it? Or am I missing the point of the warning?

Thanks for any info! ]]> C++ Programming Swerve http://cboard.cprogramming.com/cplusplus-programming/121802-basic-operator-overloading-question.html OpenAL sources limit http://cboard.cprogramming.com/game-programming/121801-openal-sources-limit.html Fri, 20 Nov 2009 17:56:30 GMT Hello! My computer game uses OpenAL. I have recently encountered a problem: I can not generate as many sources as I want. It gives me this error: Code: --------- There are not enough non-memory resources to create all the requested sources, or the array pointer is not valid. --------- I... Hello!
My computer game uses OpenAL. I have recently encountered a problem: I can not generate as many sources as I want. It gives me this error:
Code:
There are not enough non-memory resources to create all the requested sources, or the array pointer is not valid.
I don't actually understand what they mean by "non-memory resources". What does the count of possible sources depend on? How can I detect the possible count of sources? Some computers seem to allow much more sources. ]]> Game Programming moment http://cboard.cprogramming.com/game-programming/121801-openal-sources-limit.html C and RS232 problem http://cboard.cprogramming.com/linux-programming/121800-c-rs232-problem.html Fri, 20 Nov 2009 16:39:55 GMT Hi all,

I'm in troubles in writing C drivers for a device using RS232 port.
I cannot establish any communications between my linux box and that device! On the other hand I'm sure the RS232 on the device is working properly because using a hyperterminal on another Windows machine everything works fine.

Here is what is reported in the manual of the device:

"The RS232 communication parameters are:
9600 BAUD, 8 BIT, NO PARITY, 1 STOP BIT (8N1)
...
Each command is an ASCII string, and must be terminated by a Carriage Return character[...] The responses are terminated by a Carriage Return character."

Here is my code:

Code:
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <termios.h>
#include <stdlib.h>

int open_port(char *port)
{

  int fd;
  if (!port)
    return -1;
  if ((fd=open(port,O_RDWR | O_NOCTTY | O_NDELAY))<0)
    return -2;
  fcntl(fd,F_SETFL,0);
  return fd;
}

void configure_port(int fd)
{
  struct termios newtio;
  bzero(&newtio,sizeof(newtio));
  newtio.c_cflag = BAUDRATE | CS8 | CLOCAL | CREAD ;
  newtio.c_iflag = IGNPAR | ICRNL;
  newtio.c_oflag=0;
  newtio.c_lflag=ICANON;
  tcflush(fd,TCIFLUSH);
  tcsetattr(fd,TCSANOW,&newtio);
}

int main (int argc, char **argv)
{
  int fd;
  char PORT[]="/dev/ttyUSB0";
  int status;
  char buffer[255];

  if ((fd=open_port(PORT))<0)
    {
      printf("Error in opening serial port fd=%d\n",fd);
      return -1;
    }

  configure_port(fd);

  if ((status=write(fd,"SE\r",3))<3)
  {
      printf("Error in writing on serial port\n");
      return -1;
    }

  status=read(fd,buffer,255);
  buffer[status]=0;
  printf(":%s:%d\n",buffer,status);
  return 0;
}
This code is compiled without any errors or warnings but unfortunately I cannot read correct values from the device (the device should respond 2 digits ASCII
code terminated with Carriage Return character to the command SE).
In particular sometimes it happens to read "SE\r" (so exactly the same command I write on the RS232 from the pc) and in some other cases the read values are wrong in format and in length.
I cannot figure out where the problem is. I guess it is a rs232 configuration problem because as I told you using hyperterminal on Windows everything is ok but I really did not realize what is going wrong.
Maybe the problem is that I'm using a serial to usb converter and it needs further configuration I'm missing? (The same converter works with hyperterminal).
By the way here is the output of my linux box when I plug in the converter:

usb 2-1: new full speed USB device using uhci_hcd and address 13
usb 2-1: configuration #1 chosen from 1 choice
pl2303 2-1:1.0 pl2303 converter detected
usb 2-1: pl2303 converter now attached to ttyUSB0

Any suggestions?

Any help is really appreciated.

Thank you for your attention.

Bye ]]> Linux Programming gda http://cboard.cprogramming.com/linux-programming/121800-c-rs232-problem.html C Escape sequences http://cboard.cprogramming.com/c-programming/121799-c-escape-sequences.html Fri, 20 Nov 2009 15:06:47 GMT Apart from \n and \t escape sequnces, which escape sequences can be written into code and be "invisible" to the user?

For example;
char a='
'

In between the ' ' is a \n when the program reads it. How about other Escapes? Can i find them on the keyboard?

For example \r, \v etc...

The reason im asking this is because im writing a syntax checker in C and i want to know which escape sequences count more then 1 blank, and are they all writtable by keyboard. ]]> C Programming Tool http://cboard.cprogramming.com/c-programming/121799-c-escape-sequences.html Bison/Yacc shift/reduce reduce/reduce http://cboard.cprogramming.com/tech-board/121798-bison-yacc-shift-reduce-reduce-reduce.html Fri, 20 Nov 2009 14:15:12 GMT problem solved - cant find delete button for post problem solved - cant find delete button for post ]]> Tech Board AnthonyGould http://cboard.cprogramming.com/tech-board/121798-bison-yacc-shift-reduce-reduce-reduce.html