Compilare: main.cpp: In function 'int main()': main.cpp:17:5: warning: this 'for' clause does not guard... [-Wmisleading-indentation] for ( j = 2*i; j <= n; j += i) ^~~ main.cpp:19:9: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'for' for(i=1;i<=n;i++) ^~~ main.cpp:12:20: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%lld",&n); ^