Compilare: main.cpp: In function 'int main()': main.cpp:18:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (size_t i = 0; i < n; i++) ~~^~~ main.cpp:20:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (size_t j = 0; j < n; j++) ~~^~~ main.cpp:26:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (size_t k = 0; k < n; k++) ~~^~~ main.cpp:28:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (size_t i = 0; i < n; i++) ~~^~~ main.cpp:30:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (size_t j = 0; j < n; j++) ~~^~~ main.cpp:40:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (size_t i = 0; i < n; i++) ~~^~~ main.cpp:42:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (size_t j = 0; j < n; j++) ~~^~~ main.cpp:44:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] o << a[i][j] << " \n"[j == n - 1]; ~~^~~~~~~~