started migration stack->tree

oper.c

@@ -2,7 +2,23 @@
 #include <malloc.h>
 #include "lceb.h"
 
-unsigned ncombinations(nops, len)
+static char *combs[1024]; /* should be dynamic */
+static int ncombs=0;
+
+void print_comb(n)
+    int n;
+{
+    printf("comb %d/%d=[%s]\n", n, ncombs, combs[n]);
+}
+void print_combs()
+{
+    int i;
+    printf("op combs: ");
+    for (i=0; i<ncombs; ++i)
+        printf("%s ", combs[i]);
+    putchar('\n');
+}
+static unsigned n_combine(nops, len)
     int nops, len;
 {
     int result = 1;
@@ -15,7 +31,7 @@ unsigned ncombinations(nops, len)
     return result;
 }
 
-char *combination(ops, len, n)
+static char *combine(ops, len, n)
     char *ops;                                    /* string to combine */
     int len;                                      /* len of result */
     int n;                                        /* iteration # */
@@ -35,6 +51,30 @@ char *combination(ops, len, n)
     return res;
 }
 
+void gen_combinations(nops)
+    int nops;
+{
+    char *ops="+-*/";
+    int i, n_combs;
+    int len_ops=strlen(ops);
+
+    n_combs=n_combine(len_ops, nops);
+    printf("gen: n=%d\n", n_combs);
+    for (i=0; i<n_combs; ++i) {
+        combs[ncombs]=strdup(combine(ops, nops, i));
+        ncombs++;
+    }
+}
+int n_combs()
+{
+    return ncombs;
+}
+char *nth_comb(n)
+    int n;
+{
+    return combs[n];
+}
+
 #ifdef STANDALONE
 int main(ac, av)
     int ac;
@@ -45,10 +85,10 @@ int main(ac, av)
     int i, j, nops, ncombs;
 
     nops=atoi(*(av+1));
-    ncombs=ncombinations(len_ops, nops);
+    ncombs=n_combine(len_ops, nops);
     printf("# operators combinations : %d\nlist = ", ncombs);
     for (i=0; i<ncombs; ++i) {
-        p=combination(ops, nops, i);
+        p=combine(ops, nops, i);
         printf("[%s]\n", p);
         //for (j=0; j<4; ++j)
         //    distribute(j, p);