Splitting csv large files into small files with dynamic names using C++ - c++

Question

I am a beginner, so I apologise if my question looks childish. I have 38 large files in a folder. I want to split each of the files into smaller parts with dynamic name. Line 1 to line 13 works well. The challenge is in line 16-19. The output shows that the whole data from the ifstream is not appearing as char. This error makes it difficult to split the files. Please what am I getting wrong
#define SEGMENT 728300 //approximate target size of small file
using namespace std;
long file_size(char *name);//function definition below
int main(int argc, char **argv)
{
char input_file_1[100]; // input file
strcpy(input_file_1,argv[1]);
string PathToData = "path to the files";
TString name = PathToData+input_file_1;
std::cout << "Reading file " << name << endl;
char getdata[35000];
ifstream csv_db(name);
while(csv_db.getline(getdata,sizeof(csv_db)))
if (csv_db.eof())
csv_db.close();
int segments=0, i, accum;
FILE *fp1, *fp2;
unsigned int huga=strlen(getdata);
char largeFileName[huga + 100]; // Make sure there's enough space
strcpy(largeFileName, getdata);
std::cout << largeFileName << endl;
std::cout << largeFileName << endl;
long sizeFile = file_size(largeFileName);
segments = sizeFile/SEGMENT + 1980;//ensure end of file
char filename[360]={"path to folder where to keep the result"};
char smallFileName[360];
char line[1080];
fp1 = fopen(largeFileName, "r");
if(fp1)
{
for(i=1980;i<segments;i++)
{
accum = 0;
sprintf(smallFileName, "%s%d.csv", filename, i);
fp2 = fopen(smallFileName, "w");
if(fp2)
{
while(fgets(line, 1080, fp1) && accum <= SEGMENT)
{
accum += strlen(line);//track size of growing file
fputs(line, fp2);
}
fclose(fp2);
}
}
fclose(fp1);
}
return 0;
}
long file_size(char *name)
{
FILE *fp = fopen(name, "rb"); //must be binary read to get bytes
long size=-1;
if(fp)
{
fseek (fp, 0, SEEK_END);
size = ftell(fp)+1;
fclose(fp);
}
return size;
}