Compilare: user.cpp: In function ‘int main()’: user.cpp:17:32: warning: left operand of comma operator has no effect [-Wunused-value] for(int i = 1, j = k; i <= n - k + 1, j <= n; i++, j++) sum += s[i][j]; ^ user.cpp:20:32: warning: left operand of comma operator has no effect [-Wunused-value] for(int i = 1, j = k; i <= n - k + 1, j <= n; i++, j++) sum += s[j][i]; ^ user.cpp:23:40: warning: left operand of comma operator has no effect [-Wunused-value] for(int i = n - k + 1, j = 1; i >= 1, j <= n - k + 1; i--, j++) sum += s[j][i]; ^ user.cpp:26:32: warning: left operand of comma operator has no effect [-Wunused-value] for(int i = n, j = k; i >= k, j <= n; i--, j++) sum += s[j][i]; ^