examples/gcoap: fix post/put without port number

examples/gcoap/gcoap_cli.c

@@ -233,7 +233,13 @@ int gcoap_cli_cmd(int argc, char **argv)
         apos++;
     }
 
-    if (argc == apos + 3 || argc == apos + 4) {
+    /*
+     * "get" (code_pos 0) must have exactly apos + 3 arguments
+     * while "post" (code_pos 1) and "put" (code_pos 2) and must have exactly
+     * apos + 4 arguments
+     */
+    if (((argc == apos + 3) && (code_pos == 0)) ||
+        ((argc == apos + 4) && (code_pos != 0))) {
         gcoap_req_init(&pdu, &buf[0], GCOAP_PDU_BUF_SIZE, code_pos+1, argv[apos+2]);
         if (argc == apos + 4) {
             memcpy(pdu.payload, argv[apos+3], strlen(argv[apos+3]));