Compilare: user.cpp: In function ‘int main()’: user.cpp:63:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < apm.size(); i++){ ^ user.cpp:39:15: warning: unused variable ‘x’ [-Wunused-variable] int i, j, x, y, c; ^ user.cpp:39:18: warning: unused variable ‘y’ [-Wunused-variable] int i, j, x, y, c; ^ user.cpp:39:21: warning: unused variable ‘c’ [-Wunused-variable] int i, j, x, y, c; ^