BSD 4_1c_2 release

[unix-history] / usr / src / lib / libc / stdio / gcvt.c

/* @(#)gcvt.c   4.1 (Berkeley) 12/21/80 */
/*
* gcvt  - Floating output conversion to
* minimal length string
*/

char    *ecvt();

char *
gcvt(number, ndigit, buf)
double number;
char *buf;
{
       int sign, decpt;
       register char *p1, *p2;
       register i;

       p1 = ecvt(number, ndigit, &decpt, &sign);
       p2 = buf;
       if (sign)
               *p2++ = '-';
       for (i=ndigit-1; i>0 && p1[i]=='0'; i--)
               ndigit--;
       if (decpt >= 0 && decpt-ndigit > 4
        || decpt < 0 && decpt < -3) { /* use E-style */
               decpt--;
               *p2++ = *p1++;
               *p2++ = '.';
               for (i=1; i<ndigit; i++)
                       *p2++ = *p1++;
               *p2++ = 'e';
               if (decpt<0) {
                       decpt = -decpt;
                       *p2++ = '-';
               } else
                       *p2++ = '+';
               *p2++ = decpt/10 + '0';
               *p2++ = decpt%10 + '0';
       } else {
               if (decpt<=0) {
                       if (*p1!='0')
                               *p2++ = '.';
                       while (decpt<0) {
                               decpt++;
                               *p2++ = '0';
                       }
               }
               for (i=1; i<=ndigit; i++) {
                       *p2++ = *p1++;
                       if (i==decpt)
                               *p2++ = '.';
               }
               if (ndigit<decpt) {
                       while (ndigit++<decpt)
                               *p2++ = '0';
                       *p2++ = '.';
               }
       }
       if (p2[-1]=='.')
               p2--;
       *p2 = '\0';
       return(buf);
}