Compilare: user.cpp: In function ‘int main()’: user.cpp:54:9: warning: unused variable ‘i’ [-Wunused-variable] int i, k, p, val, val2, val3; ^ user.cpp:57:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("qmatrix.in","r",stdin); ^ user.cpp:58:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("qmatrix.out","w",stdout); ^ user.cpp:60:45: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d\n", &n, &val, &val2, &m); ^ user.cpp:85:40: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%c%d%d\n", &tip, &k, &p); ^