diff --git a/desktop_version/src/UtilityClass.cpp b/desktop_version/src/UtilityClass.cpp
index 9c9df3fd..4d341dce 100644
--- a/desktop_version/src/UtilityClass.cpp
+++ b/desktop_version/src/UtilityClass.cpp
@@ -269,7 +269,7 @@ bool is_number(const char* str)
 {
 	for (int i = 0; str[i] != '\0'; i++)
 	{
-		if (!SDL_isdigit(static_cast<unsigned char>(str[i])) && (i != 0 || str[0] != '-'))
+		if (!SDL_isdigit(str[i]) && (i != 0 || str[0] != '-'))
 		{
 			return false;
 		}