Compilare: user.cpp: In function ‘int main()’: user.cpp:27:10: warning: statement has no effect [-Wunused-value] for(n;n>0;n--){ ^ user.cpp:30:12: warning: statement has no effect [-Wunused-value] for(a;a<=b;a++){ ^ user.cpp:26:26: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%lld",&n); ^ user.cpp:28:35: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%lld%lld",&a,&b);; ^