Help Please. Char Arrays

[n00by]

hi, i have to write a program that converts roman numerals to regular numbers and it takes all the info from the commandline, like so: "% roman MMIV".
here is what takes the input.

int main(int argc, char* argv[])

how can i take argv[] and store anything the user puts in into another array.

for example, let's say the user inputs "roman MCI".
how can i make an array that goes through each letter with a for loop and prints out each letter separately.
like
M
C
I
help please.

edit: i only need help on this for now. i'll work on the rest by myself. thanks

[Thantos]

assuming that MMCI was the first parameter to the program.

char buffer[10];
int count=0;

for (count=0; argv[1][count] != '\0' && count < 10; count++)
  buffer[count] = argv[1][count];

[OOPboredom]

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

int main(int argc, char *argv[])
{
	char *pNumerals;
	int i;
	
	/* check for correct number of command-line arguments */
	if (argc != 2)
	{
		exit(1);
	}
	
	/* allocate memory and copy string from argv */
	pNumerals = malloc( (strlen(argv[1])) + 1);
	strcpy(pNumerals, argv[1]);
	
	/* loop through the characters of pNumerals and print */
	for (i = 0; i <= strlen(pNumerals) - 1; i++)
	{
		printf("%c\n", *(pNumerals + i));
	}
	
	/* deallocate the memory allocated to pNumerals */
	if (pNumerals != NULL)
	{
		free(pNumerals);
	}
	
	return 0;	
}

[n00by]

assuming that MMCI was the first parameter to the program.

char buffer[10];
int count=0;

for (count=0; argv[1][count] != '\0' && count < 10; count++)
  buffer[count] = argv[1][count];

thanks that worked.

[n00by]

hi, how can i get this program to function properly. if "IX" is entered, i get 11 instead of 9. i wanted to write an equation where if the one letter was smaller than the next (IX), then subtract 2 times the value of the first. how can i incorporate that into my program? thanks

#include <stdio.h>

int main(int argc, char* argv[])
{
  int ctr,sum=0,count;
  char caro[11];

  for (count=0; argv[1][count] != '\0' && count < 11; count++)
    {
      caro[count] = argv[1][count];

      switch(caro[count])
        {
        case 'M':
          sum += 1000;
          break;
        case 'D':
          sum += 500;
          break;
        case 'C':
          sum += 100;
          break;
        case 'L':
          sum += 50;
          break;
        case 'X':
          sum += 10;
          break;
        case 'V':
          sum += 5;
          break;
        case 'I':
          sum += 1;
          break;
        default:
          printf("Illegal letter encountered!\n");
          break;
        }
    }

  /*
  for(ctr = 0; ctr < 11; ctr++)
    {
      if(caro[ctr] < caro[ctr+1])
        sum -= (2*caro[ctr]);
    }
  */

  if(argc > 2)
    printf("Usage: roman <numeral>\n");
  else
    printf("The decimal equivalent of %s is %d\n", argv[1], sum);
}

[Thantos]

To do this effectivaly you need to change your algroithm.

While you are parsing (looking through) argv[0] you need to look at the current character and the next character to see if that one has a larger roman value then the one you are looking at.

Let me step you through an example:

XCXIX (not sure if this is a truely valid one but its good enough for a test)

Step 1) assign a pointer to the first character:
2) Get value of current character: 10
3) Look at value of next character: 100
4) Is 100 > 10? Yes
5) Since it is we'll take the value of 100 - 10 and add it to our sum.
6) Move pointer two places
7) We should be pointing to the second X
8) Get value of current character: 10
9) Get value of next character: 1
10) is 1 > 10? No
11) add value of current character to sum;
12) move pointer one character
13) Now we are pointing at the I
14) Get value of current character: 1
15) Get value of next character: 10
16) Is 10 > 1? Yes
17) Add the value of 10 - 1 to sum
18) Move pointer to places
19) Well now we are pointing to the end so we stop looking at the string

20) Display the sum

Also siince you aren't actually using the copied values from argv[1] you should just use a character pointer.

say you had:

char str[]="XIV";

You could parse it as such:

char *ptr;
for ( ptr = str; *ptr != '\0'; ) /* The body will control the ptr position */

To move the pointer ptr forward one position it would be

ptr++;

and to move two positions

 ptr += 2;

Hope this helps