2.9BSD - /usr/src/cmd/learn/selunit.c

   1: #include "stdio.h"
   2: #include "lrnref"
   3: 
   4: int nsave   = 0;
   5: 
   6: selunit()
   7: {
   8:     char fnam[20], s[50];
   9:     static char dobuff[50];
  10:     char posslev[20][20];
  11:     int diff[20], i, k, m, n, best, alts;
  12:     FILE *f;
  13:     char zb[200];
  14:     static char saved[20];
  15: 
  16:     while (ask) {
  17:         printf("What lesson? ");
  18:         fflush(stdout);
  19:         gets(dobuff);
  20:         if (strcmp(dobuff, "bye") == 0)
  21:             wrapup(0);
  22:         level = todo = dobuff;
  23:         sprintf(s, "../../%s/L%s", sname, dobuff);
  24:         if (access(s, 04) == 0)
  25:             return;
  26:         printf("no such lesson\n");
  27:     }
  28:     alts = 0;
  29: retry:
  30:     f=scrin;
  31:     if (f==NULL) {
  32:         sprintf(fnam, "../../%s/L%s", sname, level);
  33:         f = fopen(fnam, "r");
  34:         if (f==NULL) {
  35:             fprintf(stderr, "No script for lesson %s.\n", level);
  36:             wrapup(1);
  37:         }
  38:         while (fgets(zb, 200, f)) {
  39:             trim(zb);
  40:             if (strcmp(zb, "#next")==0)
  41:                 break;
  42:         }
  43:     }
  44:     if (feof(f)) {
  45:         printf("Congratulations; you have finished this sequence.\n");
  46:         fflush(stdout);
  47:         todo = 0;
  48:         return;
  49:     }
  50:     for(i=0; fgets(s, 50, f); i++) {
  51:         sscanf(s, "%s %d", posslev[i], &diff[i]);
  52:     }
  53:     best = -1;
  54:     /* cycle through lessons from random start */
  55:     /* first try the current place, failing that back up to
  56: 	     last place there are untried alternatives (but only one backup) */
  57:     n = grand()%i;
  58:     for(k=0; k<i; k++) {
  59:         m = (n+k)%i;
  60:         if (already(posslev[m],0)) continue;
  61:         if (best<0) best=m;
  62:         /* real alternatives */
  63:         alts++;
  64:         if (abs(diff[m]-speed) < abs(diff[best]-speed))
  65:             best=m;
  66:     }
  67:     if (best < 0 && nsave) {
  68:         nsave--;
  69:         strcpy(level, saved);
  70:         goto retry;
  71:     }
  72:     if (best <0) {
  73:         /* lessons exhausted or missing */
  74:         printf("Sorry, there are no alternative lessons at this stage.\n");
  75:         printf("See someone for help.\n");
  76:         fflush(stdout);
  77:         todo = 0;
  78:         return;
  79:     }
  80:     strcpy (dobuff, posslev[best]);
  81:     if (alts>1) {
  82:         nsave=1;
  83:         strcpy (saved, level);
  84:     }
  85:     todo = dobuff;
  86:     fclose(f);
  87: }
  88: 
  89: abs(x)
  90: {
  91:     return(x>=0? x: -x);
  92: }
  93: 
  94: grand()
  95: {
  96:     static int garbage;
  97:     int a[2], b;
  98: 
  99:     time(a);
 100:     b = a[1]+10*garbage++;
 101:     return(b&077777);
 102: }

Defined functions

Defined variables