/*  spltlgfl.cpp  by K.Tsuru  */
/*
Split the decimal part of large number file in the form
3.+
1415...

exsample               large file name              lines        out file
SplitLargeFile("ChudnovskysPi[1billion].dat", 1000000,"ChudPi%02d.dat");
*/
#include <stdlib.h>
#include <fstream>
#include <string.h>
using namespace std;
int SplitLargeFile(const char* largeFileName, const long fileLineUnit, const char* outFNameFormat)
{
    const int buffLength = 500;
    char splitFname[257], buff[buffLength];
    bool point = false; // decimal point
    ifstream read(largeFileName, ios::in);
    while(!point && !read.eof()) { // search point '.'
        read.getline(buff, buffLength, '\n');
        if(strchr(buff, '.')) point = true;
    }
    if(!point) return -1;  // not decimal file

    ofstream fout;
    int fNo = 1, line = 1;
    while(!read.eof()) {
        sprintf(splitFname, outFNameFormat, fNo);
        fout.open(splitFname, ios::out);
        do { // write one block(a split file)
            read.getline(buff, buffLength, '\n');
            fout << buff << endl; line++;
            if(line > fileLineUnit){
                line = 1;   fNo++;
                fout.close(); break;
            }
        } while(strlen(buff));
    }
    return fNo;
}