vector<float> = {10, 3.4f, 0.22f}; //I just wrote this here may contains some sytax errors
vector<char> = {'A', 'B', 'D'};
vector<int> = {-100, 100, 100000};

ofstream str = ...
for(int i = 0; i < arrayA.size(); ++i)
{
   str.write((char*)&arrayA[i]);
   str.write((char*)&arrayB[i]);
   str.write((char*)&arrayC[i]);
}
ofstream.close();