Compilare: user.cpp:2:6: warning: ISO C++ forbids declaration of ‘main’ with no type [-Wreturn-type] main(){long long n;fscanf(fopen("drepte2.in","r"),"%lld",&n);fprintf(fopen("drepte2.out","w"),"%lld",n*(n+1)/2+1);} ^ user.cpp: In function ‘int main()’: user.cpp:2:61: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] main(){long long n;fscanf(fopen("drepte2.in","r"),"%lld",&n);fprintf(fopen("drepte2.out","w"),"%lld",n*(n+1)/2+1);} ^