Thread: Merging into a number.

Hello guys!

I am trying to merge a number which is contained in seperate indexes of an array.

So for example I have [0] = 4, [1] = 3, [2] = 7.

That would save into a variable of type int the number "437".

Any number of indexes is possible upto the maximum of int. Thats somewhere around 32000 right?

I am unsure how would be the easier way to do this.

You could either put the number in an array and convert it using atoi() - OR - you could use modular arithmetic to merge it, eg:

437 = (4 * 100) + (3 * 10) + (7 * 1).

When dealing with absurdly large numbers, you're gonna have to implement some kind of a handler for it yourself, or use an external library. You could also just use an array to do it and handle the carry yourself.

This is what Ive done, but it seems I was way off, and it doesnt work as planned.

Code:

#include <stdio.h>

int array[] = {3,5,0,7,4};

int main()
{
  int x;

  printf("%s", array);
  x = my_getnbr(array);
  printf("\n%d", x);
}



int     my_getnbr(char *str)
{
  int x, y, z;
  y = 0, x = 0, z = 0;

  while (*str != '\0')
    {
      str++;
        y++;
    }
  while (x <= y)
    {
      while (z <= *str[x])
	{
	if (str[x] = 0)
          z = z + 0;
        z = z + 10000;
	}
      str++;
      while (z <= *str[x])
	{
	if (str[x] = 0)
          z = z + 0;
        z = z + 1000;
	}
      str++;
      while (z <= *str[x])
        {
        if (str[x] = 0)
          z = z + 0;
        z = z + 100;
        }
      str++;
      while (z <= *str[x])
        {
          if (str[x] = 0)
            z = z + 0;
        z = z + 10;
        }
      str++;
      while (z <= *str[x])
	{
	if (str[x] = 0)
          z = z + 0;
        z = z + 1;
	}
    }
}

if (str[x] = 0)
z = z + 0;What does this do? Absolutely nothing. Adding with zero is meaningless.

Actually it does do something, just not what was inteneded. It sets str[x] to 0 which then causes the stuff in the if statement to never run, which dident matter beacuase it never did anything anyway. For a comparison it should really have been:

if (str[x] == 0)

I'll work on it more, and see if I can come up with something.

Thanks for the help

This is the code I have now:

It doesnt work and the compiler gives no error. I dont understand why.

(So far it should work, if a number has no zeros in it anyway)

Code:

#include <stdio.h>

char array[5] = {'3','5','2','7','4'};

int main()
{
  int x;
  int y;

  for (y = 0; y < 5; y++)
  {
      printf("&#37;c", array[y]);
  }
  
  x = my_getnbr(array);
  printf("\n%d", x);
  
  system("PAUSE");
  return 0;
  
}



int my_getnbr(char *str)
{
  int x, y, z;
  y = 0, x = 0, z = 0;

  while (*str != '\0')
    {
      str++;
        y++;
    }
  if (y == 1)
     z = z * str[0];
  if (y == 2)
     z = str[1] + (str[0] * 10);
  if (y == 3)
     z = str[2] + (str[1] * 10) + (str[0] * 100);
  if (y == 4)
     z = str[3] + (str[2] * 10) + (str[1] * 100) + (str[0] * 1000);
  if (y == 5)
     z = str[4] + (str[3] * 10) + (str[2] * 100) + (str[1] * 1000) + (str[0] * 10000);
     
     return z;
}

Use a loop

int result = 0;

Then in a loop
result = result * 10 + ( str[ i ] - '0' );

Im sorry I couldn't quite grasp that.

Use a loop where? One for the whole function?

Again Im sorry but I dont understand.

If result = 0 then wont result = result * 10 always give you zero?