Nan checks for ncr and fac

.gitignore

@@ -0,0 +1,13 @@
+# binaries from make
+bench
+example
+example2
+example3
+repl
+repl-readline
+smoke
+smoke_pr
+*.exe
+
+# object files
+*.o

Makefile

@@ -40,4 +40,4 @@ repl-readline.o: repl.c
 	$(CC) -c $(CCFLAGS) $< -o $@
 
 clean:
-	rm -f *.o *.exe example example2 example3 bench repl smoke_pr smoke
+	rm -f *.o *.exe example example2 example3 bench repl repl-readline smoke_pr smoke

tinyexpr.c

@@ -122,7 +122,7 @@ void te_free(te_expr *n) {
 static double pi(void) {return 3.14159265358979323846;}
 static double e(void) {return 2.71828182845904523536;}
 static double fac(double a) {/* simplest version of fac */
-    if (a < 0.0)
+    if (a < 0.0 || isnan(a))
         return NAN;
     if (a > UINT_MAX)
         return INFINITY;
@@ -136,7 +136,7 @@ static double fac(double a) {/* simplest version of fac */
     return (double)result;
 }
 static double ncr(double n, double r) {
-    if (n < 0.0 || r < 0.0 || n < r) return NAN;
+    if (n < 0.0 || r < 0.0 || n < r || isnan(n) || isnan(r)) return NAN;
     if (n > UINT_MAX || r > UINT_MAX) return INFINITY;
     unsigned long int un = (unsigned int)(n), ur = (unsigned int)(r), i;
     unsigned long int result = 1;