Compilare: user.cpp: In function ‘int main()’: user.cpp:24:24: warning: left operand of comma operator has no effect [-Wunused-value] for(int i=1, j=1; i<=n, j<=m; i++, j++) ^ user.cpp:18:18: warning: unused variable ‘f’ [-Wunused-variable] int n, m, q, f; ^ user.cpp:15:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("gauss.in", "r", stdin); ^ user.cpp:16:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("gauss.out", "w", stdout); ^ user.cpp:19:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ user.cpp:22:35: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lf", &a[i][j]); ^