Compilare: main.cpp: In function 'int main()': main.cpp:19:9: warning: unused variable 'x1' [-Wunused-variable] int x1,x2,y1,y2; ^~ main.cpp:19:12: warning: unused variable 'x2' [-Wunused-variable] int x1,x2,y1,y2; ^~ main.cpp:19:15: warning: unused variable 'y1' [-Wunused-variable] int x1,x2,y1,y2; ^~ main.cpp:19:18: warning: unused variable 'y2' [-Wunused-variable] int x1,x2,y1,y2; ^~