UNIX 6th Ed. - /usr/source/s4/atoi.c

   1: atoi(ap)
   2: char *ap;
   3: {
   4:     register n, c;
   5:     register char *p;
   6:     int f;
   7: 
   8:     p = ap;
   9:     n = 0;
  10:     f = 0;
  11: loop:
  12:     while(*p == ' ' || *p == '	')
  13:         p++;
  14:     if(*p == '-') {
  15:         f++;
  16:         p++;
  17:         goto loop;
  18:     }
  19:     while(*p >= '0' && *p <= '9')
  20:         n = n*10 + *p++ - '0';
  21:     if(f)
  22:         n = -n;
  23:     return(n);
  24: }

Defined functions