Compilare: main.cpp: In function 'int main()': main.cpp:25:9: warning: unused variable 'ok' [-Wunused-variable] int ok=1; ^~ main.cpp:13:22: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d",&n); ^ main.cpp:16:11: warning: iteration 2000005 invokes undefined behavior [-Waggressive-loop-optimizations] v[i]=1; ~~~~^~ main.cpp:14:12: note: within this loop for(i=2;i<=nmax;i++) ^