Compilare: main.cpp: In function 'int main()': main.cpp:68:10: warning: statement has no effect [-Wunused-value] for(n;n>0;n--){ ^ main.cpp:67:26: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%lld",&n); ^ main.cpp:69:37: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%lld%lld",&a,&b); ^ main.cpp: In function 'void ciuruiala()': main.cpp:21:16: warning: iteration 999998 invokes undefined behavior [-Waggressive-loop-optimizations] if(!c[i]){ ~~~^ main.cpp:20:19: note: within this loop for(int i=2; i<=maxn; i++){ ^