Compilare: user.cpp: In function ‘int main()’: user.cpp:39:28: warning: variable ‘b’ set but not used [-Wunused-but-set-variable] unsigned int l,r,a,b,k; ^ user.cpp:9:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("summax.in","r",stdin); ^ user.cpp:10:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("summax.out","w",stdout); ^ user.cpp:13:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%u%u%u%u",&t,&n,&st,&dr); ^ user.cpp:15:49: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(j=1;j<=i;j++) scanf("%u",&sum[i][j]); ^