Compilare: main.cpp: In function 'int main()': main.cpp:16:3: warning: this 'for' clause does not guard... [-Wmisleading-indentation] for(i=2;i*i<=nmax;i++) ^~~ main.cpp:20:5: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'for' int ok=1; ^~~ main.cpp:11:22: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d",&n); ^ main.cpp:14:11: warning: iteration 1000005 invokes undefined behavior [-Waggressive-loop-optimizations] v[i]=1; ~~~~^~ main.cpp:12:12: note: within this loop for(i=2;i<=nmax;i++) ^