Can someone break down this code line by line for me and tell me what each line means?

int readBooks(string filename, string titles[], string authors[],int currentSize,int maxCapacity){

ifstream inFile(filename.c_str());

if(!inFile){

return -1;

}

string line;

int size=currentSize;

while(getline(inFile,line) && size

istringstream stream(line);

string token; //to represent a single token

getline(stream,token,',');

authors[size]=token;

getline(stream,token,',');

titles[size]=token;

size++;

}

inFile.close();

return size;

}