taken into account of a NULL query string

main.c

@@ -4,21 +4,20 @@
 #include <string.h>
 #include <sqlite3.h>
 
-inline char *get_filename(const char c) {
-    char *qout; 
-    switch(c) {
-        default:
-            qout = "queries/mranks.sql";
-            break;
-        case 'm':
-            qout = "queries/mleaderboard-ojoin.sql";
-            break;
-        case 'p':
-            qout = "queries/rplayers.sql";
-            break;
-        case 't':
-            qout = "queries/test.txt";
-            break;
+inline char *get_filename(const char *c) {
+    char *qout = "queries/mranks.sql"; 
+    if (c != NULL) {
+        switch(*c) {
+            case 'm':
+                qout = "queries/mleaderboard-ojoin.sql";
+                break;
+            case 'p':
+                qout = "queries/rplayers.sql";
+                break;
+            case 't':
+                qout = "queries/test.txt";
+                break;
+        }
     }
     return qout;
 }
@@ -58,7 +57,7 @@ inline void print_tblheader(const char *c) {
     printf("%s", out);
 }
 
-//display and format the results of the query.
+// display and format the results of the query.
 void qresult(sqlite3_stmt *sp, const char *c) {
     int e;
     unsigned int i;
@@ -74,9 +73,12 @@ void qresult(sqlite3_stmt *sp, const char *c) {
     printf("</TABLE>");
 }
 
+// const char 'sql' is never NULL.
+// const char 'str' may be NULL, however it is only when 
+// the contents of mranks.sql is in const char 'sql'.
 bool executequery(const char *sql, const char *str) {
-    const char *p = strchr(str, '=') + 1;
-    const char qc = str[0];
+    const char *p = (str != NULL) ? strchr(str, '=') + 1 : NULL;
+    const char qc = (str != NULL) ? str[0] : '\0';
     sqlite3    *db;
     char       *error;
     int con = sqlite3_open("db/cts.db", &db);
@@ -103,7 +105,7 @@ bool executequery(const char *sql, const char *str) {
 // containing the data from query files.
 void getquery(const char *qs) {
     char *qf, *qp;
-    char *fname = get_filename(qs[0]);
+    char *fname = get_filename(qs);
     if (fname != NULL) { 
         FILE *f = fopen(fname, "r");
         if (f != NULL && qf != NULL) {
@@ -118,7 +120,6 @@ void getquery(const char *qs) {
         }
         fclose(f);
     }
-    qp = strchr(qs, '=') + 1; 
     executequery(qf, qs);
     free(qf);
 }
@@ -136,7 +137,8 @@ void html(void) {
               </body></html>";
     printf("%s", html_top);
  //  getquery(getenv("QUERY_STRING"));
-    getquery("map=pornstar-kaine");
+//    getquery("map=pornstar-kaine");
+    getquery(NULL);
     printf("%s", html_bot);
 }