Compilare: main.cpp: In member function 'void Graph::TS_read()': main.cpp:198:14: warning: passing NULL to non-pointer argument 1 of 'void exit(int)' [-Wconversion-null] 198 | exit(NULL); | ^~~~ In file included from /usr/include/c++/10/bits/std_abs.h:38, from /usr/include/c++/10/cmath:47, from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:41, from main.cpp:1: /usr/include/stdlib.h:617:23: note: declared here 617 | extern void exit (int __status) __THROW __attribute__ ((__noreturn__)); | ~~~~^~~~~~~~ main.cpp: In member function 'void Graph::biconex()': main.cpp:238:14: warning: passing NULL to non-pointer argument 1 of 'void exit(int)' [-Wconversion-null] 238 | exit(NULL); | ^~~~ In file included from /usr/include/c++/10/bits/std_abs.h:38, from /usr/include/c++/10/cmath:47, from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:41, from main.cpp:1: /usr/include/stdlib.h:617:23: note: declared here 617 | extern void exit (int __status) __THROW __attribute__ ((__noreturn__)); | ~~~~^~~~~~~~ main.cpp: In function 'int main()': main.cpp:379:9: warning: unused variable 'x' [-Wunused-variable] 379 | int x = 2; | ^