Compilare: user.cpp: In function ‘void opt0(int)’: user.cpp:19:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (v[mij] <= val) ^ user.cpp:25:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (v[mij] > val) ^ user.cpp:27:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (v[mij] == val) ^ user.cpp: In function ‘void opt1(int)’: user.cpp:40:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (v[mij] <= val) ^ user.cpp:46:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (v[mij] > val) ^ user.cpp: In function ‘void opt2(int)’: user.cpp:58:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (v[mij] < val) ^ user.cpp:64:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (v[mij] < val) ^