fatal error: string: No such file or directory - c++

Question

I get this message upon compiling with cmake:
In file included from scanner.lex:6:
C:\Users\uriya\CLionProjects\untitled1\output.hpp:4:10: fatal error: string: No such file or directory
4 | #include <string>
| ^~~~~~~~
compilation terminated.
make.exe[3]: *** [CMakeFiles\untitled1.dir\build.make:88: CMakeFiles/untitled1.dir/lex.yy.c.obj] Error 1
make.exe[3]: *** Waiting for unfinished jobs....
make.exe[2]: *** [CMakeFiles\Makefile2:72: CMakeFiles/untitled1.dir/all] Error 2
make.exe[1]: *** [CMakeFiles\Makefile2:84: CMakeFiles/untitled1.dir/rule] Error 2
make.exe: *** [Makefile:117: untitled1] Error 2
This is the part of the code that causes the problems:
#ifndef _236360_2_
#define _236360_2_
#include <string>
using namespace std;
namespace output {
extern const string rules[];
void printProductionRule(int ruleno);
void errorLex(int lineno);
void errorSyn(int lineno);
};
#endif
and that's the cmake input:
cmake_minimum_required(VERSION 3.13)
project(untitled1)
set(CMAKE_CXX_STANDARD 11)
add_executable(untitled1 parser.tab.cpp output.cpp lex.yy.c)
oddly enough I manage to compile it with no problems using g++ -std=c++11 -o hw2 parser.tab.cpp output.cpp lex.yy.c
what's the difference between cmake and this command?