Compilare: main.cpp: In function 'int main()': main.cpp:72:13: warning: left operand of comma operator has no effect [-Wunused-value] x1, y1, x2, y2; ^~ main.cpp:72:17: warning: right operand of comma operator has no effect [-Wunused-value] x1, y1, x2, y2; ^~ main.cpp:72:21: warning: right operand of comma operator has no effect [-Wunused-value] x1, y1, x2, y2; ^~ main.cpp:72:23: warning: right operand of comma operator has no effect [-Wunused-value] x1, y1, x2, y2; ^