C Programming Project - Have Questions about functions!!

[Mankthetank19]

Hello again, I am still new to this language still and I have a programming project that needs to be done in 2 weeks. I am getting a head start now

I have started the code already and I am trying to finish the introduction code before the conversion, which is going to be the hard part. If you look at the code, I need to use functions within each case that asks the questions for each choice, perform the operation, and display the answer.
- ex:
*"Enter the 32 bit binary IP that you want to be converted to dotted decimal ip form"
*"The answer is ####"
(I know printf and scanf can be used but I researched that using functions would be better and easier *if I knew how to use them*)

My question:
What function code should I use that would ask the question, perform the operation, and display the answer? I know the function needs to be placed within each case
**Any suggestions/assistance/information would be greatly appreciated**

Here is the project:
Project 1
project 1 menu:

***************************************
Select from one of the choices:

1) Convert from 32 bit binary(in chunks of 8 bits) ip form to dotted decimal ip form
2) Convert from dotted decimal ip form to 32 bit binary ip form
3) Convert a dotted decimal ip form to it's class
and display the network and host portions separately
4) Convert from CIDR slash notation to dotted decimal ip form
5) Convert from subnet dotted ip form to CIDR slash form
6) Quit the program

Enter your choice:
*********************************************

do not include the *s, repeatly show the menu until the user decides
to exit the program


no external documentation is required for this project, the program may be
written in C or C++ or Java or C#.

TO RECEIVE CREDIT FOR YOUR PROJECT:
email the source file as an attached file to ********.edu
use the subject heading for the email "CS211 Proj1"
(this is very critical, you may want to cut and paste this)

DUE DATE : 11/26/2008

*Code is attached

#include <stdio.h>
#include <stdlib.h>
main()
{
int choice;

do
{ printf("Select from one of the choices:\n");
  printf("1.) Convert from 32 bit binary ip form to dotted decimal ip form\n");
  printf("2.) Convert from dotted decimal ip form to 32 bit binary ip form\n");
  printf("3.) Convert a dotted decimal ip form to it's class and display the network portions separately\n");
  printf("4.) Convert from CIDR slash notation to dotted decimal ip form\n");
  printf("5.) Convert from subnet dotted ip form to CIDR slash form\n");
  printf("6.) Quit the the program\n");
printf("Enter your choice: ");
scanf(" %d", &choice);
switch (choice)
  {
case (1) : printf("1.) Convert from 32 bit binary ip form to dotted decimal ip form\n");
break;
case (2) : printf("2.) Convert from dotted decimal ip form to 32 bit binary ip form\n");
break;
case (3) : printf("3.) Convert a dotted decimal ip form to it's class and display the network portions separately\n");
break;
case (4) : printf("4.) Convert from CIDR slash notation to dotted decimal ip form\n");
break;
case (5) : printf("5.) Convert from subnet dotted ip form to CIDR slash form\n");
break;
case (6) : exit(0);
break;
default  : printf("I don't know the ");
           printf("option %d. \n", choice);
           printf("Try again. \n");
           break;
  }
system("clear");
} while(1);
}

[Mankthetank19]

After some more research and testing. I think I have the code to convert from decimal IP to 32 bit binary IP.

What does everyone think?

{
// Initialize the variables
unsigned long a,b,c,d,base10IP;

// Get the IP address from user
cout << "\nEnter an IP address in dotted quad notation (x.x.x.x)";
cout << "\nwith each section seperated by a space: ";
cin >> a >> b >> c >> d;

// Do calculations to covert IP to base 10
a *= 16777216;
b *= 65536;
c *= 256;
base10IP = a + b + c + d;

// Output new IP address
cout << "\nThe converted address is: " << base10IP << '\n';
}

[wje_lf]

Test it. Try various values. Does it work?

[Mankthetank19]

Test it. Try various values. Does it work?

I am planning to try it as soon as I get home since I am on a PC that doesn't have C. I've been playing around in notepad until I get home.

[Mankthetank19]

It doesn't work because I am using cout and cin which is not found in C but found in C++.

Does anybody have any suggestions in code that performs the same functions of cout and cin in C??

[wje_lf]

You're already familiary with printf() and fprintf(), yes?

[Mankthetank19]

If anybody wants to know the end code - here it is
Thanks for the help everyone!

//************************************************************************
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

// read an IP address in binary form
// store it into an array of 4 strings of 8 chars each
// return 1 if read successfully or 0 if an error occurred
  int readBinary(char bin[4][8]) {
  char binString[80];
  int i, j;
  int nextChar = 0;
  int len;

// read line
  printf("Enter 32-bit IP address in binary form (xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx): ");
  fflush(stdout); //flushes the output, it is needed on some version of linux/unix before scanf
  scanf("%[^\r\n]", binString);

// store binary digits into bin array
  len = strlen(binString);
  for (i=0; i<4; i++) {
    if (nextChar >= len) {
      printf("Invalid input string (too short)\n");
      return 0;
    }
    for (j=0; j<8; j++) {
// skip spaces
      while (nextChar < len && binString[nextChar] == ' ')
        nextChar++;
// end of string? break the loop
      if (nextChar >= len) {
        printf("Invalid input string (too short)\n");
        return 0;
      }
      bin[i][j] = binString[nextChar];
      nextChar++;
// only 0 and 1 accepted
      if (bin[i][j] != '0' && bin[i][j] != '1') {
        printf("Invalid input string (not a binary number)\n");
        return 0;
      }
    }
  }

// return 1 (OK)
  return 1;
}

// read an IP address in decimal dotted form
// return 1 if ok or 0 if an error occurs
  int readIPAddress(int ipaddr[]) {
  char decstring[4][4];
  int i;

// read IP address as strings
  printf("Enter 32-bit IP address in dotted decimal notation (xxx.xxx.xxx.xxx): ");
  fflush(stdout);
  if (scanf("%[^.].%[^.].%[^.].%[^\r\n]", decstring[0], decstring[1], decstring[2], decstring[3]) < 4) {
    printf("Invalid input string (wrong IP address format)\n");
    return 0;
  }

// convert each string to integer
  for (i=0; i<4; i++) {
    ipaddr[i] = atoi(decstring[i]);  // atoi converts a string to an integer
    if (ipaddr[i] < 0 || ipaddr[i] > 255) {
      printf("Invalid input string (incorrect numbers for IP address)\n");
      return 0;
    }
  }

  return 1;
}

// read an IP address slash netmask length (CIDR format)
// return 1 if ok or 0 if an error occurs
int readIPSlashAddress(int ipaddr[], int *slash) {
  char decstring[4][4];
  char slashstring[3];
  int i;

// read IP address as strings
  printf("Enter IP-address in CIDR notation (xxx.xxx.xxx.xxx/xx): ");
  fflush(stdout);
  if (scanf("%[^.].%[^.].%[^.].%[^/]/%[^\r\n]", decstring[0], decstring[1], decstring[2], decstring[3], slashstring) < 5) {
    printf("Invalid input string (wrong IP address format)\n");
    return 0;
  }

// convert each string to integer
  for (i=0; i<4; i++) {
    ipaddr[i] = atoi(decstring[i]);
    if (ipaddr[i] < 0 || ipaddr[i] > 255) {
      printf("Invalid input string (incorrect numbers for IP address)\n");
      return 0;
    }
  }

  *slash = atoi(slashstring);  // a variable and it stores the netmask-length
  if (*slash < 0 || *slash > 32) {
    printf("Invalid input string (invalid netmask length)\n");
    return 0;
  }

  return 1;
}

// read an IP address slash netmask
// return 1 if ok or 0 if an error occurs
  int readIPMaskAddress(int ipaddr[], int mask[]) {
  char decstring[4][4];
  char maskstring[4][4];
  int i;

// read IP address as strings
  printf("Enter IP-address/subnet you want converted to CIDR slash form (xxx.xxx.xxx.xxx/xxx.xxx.xxx.xxx.): ");
  fflush(stdout);
  if (scanf("%[^.].%[^.].%[^.].%[^/]/%[^.].%[^.].%[^.].%[^\r\n]", decstring[0], decstring[1], decstring[2], decstring[3],
      maskstring[0], maskstring[1], maskstring[2], maskstring[3]) < 8) {
    printf("Invalid input string (wrong IP address/netmask format)\n");
    return 0;
  }

// convert each string to integer
   for (i=0; i<4; i++) {
    ipaddr[i] = atoi(decstring[i]);
    if (ipaddr[i] < 0 || ipaddr[i] > 255) {
      printf("Invalid input string (incorrect numbers for IP address)\n");
      return 0;
    }
  }

// convert each string to integer
   for (i=0; i<4; i++) {
    mask[i] = atoi(maskstring[i]);
    if (mask[i] < 0 || mask[i] > 255) {
      printf("Invalid input string (incorrect numbers for netmask)\n");
      return 0;
    }
  }
  return 1;
}

void convertBinToDec(char bin[4][8], int dec[]) {

  int i, j;

// convert each binary group to decimal number
  for (i=0; i<4; i++) {
    dec[i] = 0;
    for (j=0; j<8; j++) {
      dec[i] *= 2;
      if (bin[i][j] == '1')
        dec[i]++;
    }
  }

}

void convertDecToBin(int dec[], char bin[4][9]) {

  int i, j;

// convert each decimal group to binary
  for (i=0; i<4; i++) {
    for (j=7; j>=0; j--) {
      bin[i][j] = (dec[i] & 1) + '0';
      dec[i] /= 2;
    }
    bin[i][8] = 0;
  }

}

// show network and host parts
void showNetworkHost(int ipaddr[], int numNetwork) {
  int i;

  printf("Network portion is: ");
  for (i=0; i<=numNetwork; i++)
    printf("%d.", ipaddr[i]);
  printf("\n");

  printf("Host portion is: ");
  for (i=numNetwork+1; i<4; i++)
    printf(".%d", ipaddr[i]);
  printf("\n");
}

void convertCIDRToNetmask(int slash, int mask[]) {

// create binary mask first, then convert to decimal
  char bin[4][8];
  int i, j;

// write 1's while slash is positive, then write 0's
  for (i=0; i<4; i++)
    for (j=0; j<8; j++) {
      if (slash > 0) {
        bin[i][j] = '1';
        slash--;
      }
      else
        bin[i][j] = '0';
    }

// convert to decimal
  convertBinToDec(bin, mask);
}

  int convertNetmaskToCIDR(int mask[], int *slash) {
// create binary mask first, then convert to slash form
  char bin[4][9];
  int i, j;
  char lastChar;

  convertDecToBin(mask, bin);

// add to slash while 1's are found
  lastChar = '1';
  *slash = 0;
  for (i=0; i<4; i++)
    for (j=0; j<8; j++) {
      if (bin[i][j] == '1') {
// once a zero is found - no more 1's should appear
        if (lastChar == '0') {
          printf("Cannot convert netmask to CIDR notation\n");
          return 0;
        }
        (*slash)++;
      }
      lastChar = bin[i][j];
    }

  return 1;
}

int main()
{
  int choice;
  char bin[4][8];
  char bin2[4][9];
  int ipaddr[4];
  int mask[4];
  int slash;

// temp string, used when reading - used to skip any remaining input after reading
// a menu option in the main menu.  The main menu scanf reads an integer.  If a temp
// string wasn't used, the next scanf trying to read a string would read an empty string 
  char temp[80];

  do
  {
    printf("\nSelect from one of the choices:\n\n");
    printf("1) Convert from 32 bit binary ip form to dotted decimal ip form\n");
    printf("2) Convert from dotted decimal ip form to 32 bit binary ip form\n");
    printf("3) Convert a dotted decimal ip form to its class and display the network and host portions separately\n");
    printf("4) Convert from IP/CIDR slash notation to dotted decimal ip form\n");
    printf("5) Convert from IP/subnet dotted ip form to CIDR slash form\n");
    printf("6) Quit the program\n");
    printf("\nEnter your choice: ");
    fflush(stdout);
    scanf("%d", &choice);
    scanf("%[^\n]", temp);
    scanf("%c", temp);

    switch (choice)
    {
      case (1) : // Convert from 32 bit binary ip form to dotted decimal ip form

                 if (!readBinary(bin))
                   break;

                 convertBinToDec(bin, ipaddr);

                 // print the resulting IP
                 printf("The address converted to decimal is: %d.%d.%d.%d\n", ipaddr[0], ipaddr[1], ipaddr[2], ipaddr[3]);

                 break;

      case (2) : // Convert from dotted decimal ip form to 32 bit binary ip form
                 if (!readIPAddress(ipaddr))
                   break;

                 convertDecToBin(ipaddr, bin2);

                 // print the results
                 printf("The address converted to binary is: %8s %8s %8s %8s\n", bin2[0], bin2[1], bin2[2], bin2[3]);
                 break;

      case (3) : // Convert a dotted decimal ip form to its class
                 if (!readIPAddress(ipaddr))
                   break;

                 if (ipaddr[0] < 128) {
                   printf("This address belongs to class A\n");
                   showNetworkHost(ipaddr, 0);
                 }
                 else if (ipaddr[0] < 192) {
                   printf("This address belongs to class B\n");
                   showNetworkHost(ipaddr, 1);
                 }
                 else if (ipaddr[0] < 224) {
                   printf("This address belongs to class C\n");
                   showNetworkHost(ipaddr, 2);
                 }
                 else if (ipaddr[0] < 240)
                   printf("This address belongs to class D\n");
                 else
                   printf("This address belongs to class E\n");

                 break;
      case (4) : // Convert from IP CIDR slash notation of to dotted decimal ip form
                 if (!readIPSlashAddress(ipaddr, &slash))
                   break;

                 convertCIDRToNetmask(slash, mask);

                 printf("IP/Netmask in dotted decimal IP form: %d.%d.%d.%d/%d.%d.%d.%d\n",
                     ipaddr[0], ipaddr[1], ipaddr[2], ipaddr[3], mask[0], mask[1], mask[2], mask[3]);

                 break;

      case (5) : // Convert from IP/subnet form to CIDR slash form
                 if (!readIPMaskAddress(ipaddr, mask))
                   break;

                 if (!convertNetmaskToCIDR(mask, &slash))
                   break;

                 printf("IP/Netmask-length in CIDR notation: %d.%d.%d.%d/%d",
                     ipaddr[0], ipaddr[1], ipaddr[2], ipaddr[3], slash);

                 break;

      case (6) : system("clear"); //clear program
                 exit(0); // close program

      default  : printf("I don't know the option %d.\n", choice);
                 printf("Try again.\n");
                 break;
    }
  } while(1);
}