lab2_3

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <malloc.h>
const char *Scale="0123456789ABCDEF";

int dig2int(char d, int from)
{
    int i;
    for (i=0; i<from; i++)
    {

        if (Scale[i]==d)
            return i;
    }
    return -1;

}
char *upcase(char *n)
{
    int z;
   for (z = 0; z != strlen(n); z++)
        n[z] = toupper(n[z]);

}
char  *convertq(char *n, int from, int to, int *error)
{
      *error = 0;
      int i,j,length,p,k;
      char *buf;
      length=strlen(n);
      p=0;
      for (i=0; i<length; i++)
        if ( dig2int(n[i], from) != -1)
            p=p*from+dig2int(n[i], from);
        else
        {
            *error = 1;
            break;
        }
      buf=(char *) calloc(100,1);
      k=99;
      length=0;
      while (1)
      {
         j=p%to;
         buf[k--]=Scale[j];
         length++;
         p=p/to;
         if (p==0) break;
      }
      j=0;
      k++;
      while (1)
      {
         buf[j++]=buf[k++];
         if (k == 100) break;
      }
      buf=(char *) realloc(buf,(length+1));
      return buf;
}
int main(int argc, char *argv[])
{
    int *from;
    int error;
    char n[100];
    int input;

    do
    {
    printf("Choose wisely:\n");
    printf("1. 16 to 10\n");
    printf("2. 8 to 10\n");
    printf("3. 10 to 2\n");
    printf("4. exit]\n");
    scanf( "%d", &input );
    getchar();
        if (input == 1)
        {
            from = 16;
            char *ans;
            printf("Enter your number: \n");
            scanf("%s", n);
            upcase(n);
            ans = convertq(n, 16, 10, &error);
            if (!error)
                printf("Result: %s\n", ans);
            else
                printf("SMT WENT WRONG\n");
        }
        if (input == 2)
        {
            from = 8;
            char *ans;
            printf("Enter your number: \n");
            scanf("%s", n);
            upcase(n);
            ans = convertq(n, 8, 10, &error);
            if (!error)
                printf("Result: %s\n", ans);
            else
                printf("SMT WENT WRONG\n");
        }
        if (input == 3)
        {
            from = 10;
            char *ans;
            printf("Enter your number: \n");
            scanf("%s", n);
            upcase(n);
            ans = convertq(n, 10, 2, &error);
            if (!error)
                printf("Result: %s\n", ans);
            else
                printf("SMT WENT WRONG\n");

        }
        if (input == 4)
        {
            break;
        }
    }
    while(1);
    return 0;

}