Compilare: main.cpp: In function 'int main()': main.cpp:46:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 1; j < Heights.size() - 1; ++j) { ~~^~~~~~~~~~~~~~~~~~~~ main.cpp:65:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 1; j < Heights.size() - 1; ++j) { ~~^~~~~~~~~~~~~~~~~~~~ main.cpp:81:17: warning: ignoring return value of 'int system(const char*)', declared with attribute warn_unused_result [-Wunused-result] system("PAUSE"); ^