dealt with a conflict (oops) and new prototype

main.h

@@ -1,5 +1,6 @@
 #ifndef MAIN_H_
 #define MAIN_H_
+#include <stdarg.h>
 int _printf(const char *format, ...);
 int _contains(const char *str, char c);
 int _strlen(const char *str);
@@ -7,6 +8,7 @@ char *_strcpy(char *dest, char *src);
 char *append(char *str, char c);
 int _puts(char *str);
 int _putchar(char c);
-char* _memset(char *str, int bval);
+char *_memset(char *str, int bval);
+int fmt(char c, va_list args);
 
 #endif