Compilare: main.cpp: In function 'int main()': main.cpp:18:3: warning: this 'for' clause does not guard... [-Wmisleading-indentation] for(i=2;i*i<=nmax;i++) ^~~ main.cpp:22:5: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'for' int ok=1; ^~~ main.cpp:32:29: warning: format '%d' expects argument of type 'int', but argument 3 has type 'long long int' [-Wformat=] fprintf(g,"%d",r); ^ 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++) ^