Compilare: user.cpp: In function ‘int main()’: user.cpp:48:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i <= n; i ++) ^ user.cpp:49:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 1; j <= n; j ++) ^ user.cpp:52:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int k = 1; k <= n; k ++) ^ user.cpp:55:60: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int si = k, sj = 1, fi = k, fj = 1; fi <= n; fi ++, fj ++) ^ user.cpp:69:60: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int si = k, sj = n, fi = k, fj = n; fi <= n; fi ++, fj --) ^ user.cpp:97:60: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int si = 1, sj = k, fi = 1, fj = k; fj <= n; fi ++, fj ++) ^