I need to read a text file(format given below) in C++

filename:test.txt

3
1,2,3,4,5
2,1,3
3,4,2,1

I need to store the top number(3) in an variable(num).
The rest, I need to store in an 2D array set[i][j];
The number of lines in the text file can be anywhere 3 to 25 lines.

I need a simple C++ code to do this. It will help me if I can have the
code by tomorrow afternoon(12/6). I will tip well for a fully working
C++ code.

Thanks in advance.

#include<stdio.h>
main()
{
FILE *fp;
fp=fopen("test.txt","rb");	
int num;
int *array[100]; /*assume maximum 100 numbers in a row*/
int test;
int i,j,k;
fscanf(fp,"%d",&num); /*get the top number*/
printf("num = %d\n",num);/*print the number*/
for(i=0;;i++)/*loop row*/
{
	for(j=0;;j++)/*loop column*/
	{
	if(fscanf(fp,"%d",&test)==-1) /*get the number till file ends*/
	goto end;		
	array[i][j]=test;	/*store it in array*/
	printf("array[%d][%d] = %d\n",i,j,array[i][j]); /*print it*/ 
	if((k=fgetc(fp))=='\n') /* if new line then goto next row*/
	break;	
	}
}
end:printf("All Done\n");/* Print all done*/
}

haha, my c++ skills aren't as ub3r l33t as his, but this gets the job done.

#include <iostream>
#include <fstream>
#include <string>
#include <stdlib.h>

using namespace std;
#define MAX_LINES 25
#define MAX_IN_LINE 50

int main() {
  //open our file
  ifstream myfile ("test.txt");
  //initialize our array's
  int myarray[MAX_LINES][MAX_IN_LINE];
  //used for knowing how many numbers are stored in each array
  int totalargs[MAX_LINES];
  //rest of variables
  string line,tempnum;
  int end=0;
  int firstarg=0,secondarg=0;
  int num;

  //set all of our arrays to be zero'd out
  memset(myarray,0,MAX_LINES*MAX_IN_LINE);
  memset(totalargs,0,MAX_LINES);

  //make sure file is opened
  if (myfile.is_open()) {
    //get a line
    getline(myfile,line);
    //the first line is the number, so set it to num
    num=atoi(line.c_str());

    while(!myfile.eof()) {
      getline(myfile,line);
      //if there is a , in the line we have gotten
      while((end=line.find(',',0))!=string::npos) {
        //get the number before the ,
        tempnum=line.substr(0,end);
        myarray[firstarg][secondarg]=atoi(tempnum.c_str());
        secondarg++;
        //erase the part of the line we have gotten
        line.erase(0,end+1);
      }
      //we will have an extra number at the end after that loop
      //this gets that last number
      tempnum=line.substr(0,line.length());
      myarray[firstarg][secondarg]=atoi(tempnum.c_str());
      //set the number of args to our array
      totalargs[firstarg]=secondarg;
      firstarg++;
      //reset arg.
      secondarg=0;
    }
  } else {
    cout << "cannot open";
  }

  //this is extra, but it just shows you your variables and that
  //they really do have numbers in them.
  cout << "num: " << num << endl;
  for (int x=0;x<firstarg;x++) {
    cout << "Array " << x+1 << ": " << myarray[x][0];
    for (int y=1;y<=totalargs[x];y++) {
      cout << "," << myarray[x][y];
    }
    cout << endl;
  }
}

#include<stdio.h>
main()
{
FILE *fp;
fp=fopen("test.txt","rb");	
int num;
int array[25][100]; /*assume maximum 100 numbers in a row*/
int test;
int i,j,k;
fscanf(fp,"%d",&num); /*get the top number*/
printf("num = %d\n",num);/*print the number*/
for(i=0;;i++)/*loop row*/
{
	for(j=0;;j++)/*loop column*/
	{
	if(fscanf(fp,"%d",&test)==-1) /*get the number till file ends*/
	goto end;		
	array[i][j]=test;	/*store it in array*/
	printf("array[%d][%d] = %d\n",i,j,array[i][j]); /*print it*/ 
	if((k=fgetc(fp))=='\n') /* if new line then goto next row*/
	break;	
	}
}
end:printf("All Done\n");/* Print all done*/
}

ljbuesch-ga..I tried your program and it worked ..thank you for the
help.can u post the same as answer.

If you want to actually use proper C++ throughout and not use C
functions and be limited by constant sized POD arrays (EVIL!) - no
bounds checking, not dynamic etc. then this is 100% C++ (AKAIK).  It
also doesn't use things like atoi() and instead converts the number
properly using istringstream >>



#include <iostream>
#include <vector>
#include <fstream>
#include <string>
#include <sstream>

using namespace std;

#pragma warning(disable: 4786)

void Tokenize(const string& str,
			  vector<string>& tokens,
			  const string& delimiters = " ");

int main(int argc, char* argv[])
{
	int num;
	string str;
	//open the file (use forward slash to avoid accidentally using escape chars)
	fstream file_op("c:/test_file.txt",ios::in);
	//get the first digit on the first line
	if (!file_op.eof()) {
		getline(file_op, str);
		istringstream i(str);
		i >> num;
	}

	//create our vector that we will use
	vector<int> vecNumbers;
	vector<int>::const_iterator vecNumbersIt;
	vector< vector<int> > vecLines;
	vector< vector<int> >::const_iterator vecLinesIt;

	//will use a vector of strings for our Tokenise() function and then iterate
	//through it converting them to numbers
	vector<string> vecString;
	vector<string>::iterator vecStringIt;

	//dont reposition the file pointer, we are already on line two
	while(!file_op.eof()) {
		getline(file_op, str);
		vecNumbers.clear();
		vecString.clear();
		//split the line on the commas
		Tokenize(str, vecString, ",");
		//for each string in the vector convert it to a number -PROPERLY -
and put it in vecNumbers
		for (vecStringIt = vecString.begin(); vecStringIt !=
vecString.end(); ++vecStringIt) {
			istringstream i(*vecStringIt);
			int x;
			i >> x;
			vecNumbers.push_back(x);
		}
		//we have every number in the line in vecNumbers, now put the
numbers into the vecLine
		vecLines.push_back(vecNumbers);
	}
	//be nice and close the file
	file_op.close();

	//OUTPUT ONLY
	cout << num << endl;
	for (vecLinesIt = vecLines.begin(); vecLinesIt != vecLines.end(); ++vecLinesIt) {
		vecNumbers = *vecLinesIt;
		for (vecNumbersIt = vecNumbers.begin(); vecNumbersIt !=
vecNumbers.end(); ++vecNumbersIt) {
			cout << *vecNumbersIt << ",";
		}
		cout << endl;
	}
	return 0;
}

void Tokenize(const string& str,
			  vector<string>& tokens,
			  const string& delimiters /*= " "*/)
{
    // Skip delimiters at beginning.
    string::size_type lastPos = str.find_first_not_of(delimiters, 0);
    // Find first "non-delimiter".
    string::size_type pos     = str.find_first_of(delimiters, lastPos);
	
    while (string::npos != pos || string::npos != lastPos)
    {
        // Found a token, add it to the vector.
        tokens.push_back(str.substr(lastPos, pos - lastPos));
        // Skip delimiters.  Note the "not_of"
        lastPos = str.find_first_not_of(delimiters, pos);
        // Find next "non-delimiter"
        pos = str.find_first_of(delimiters, lastPos);
    }
}




Hope this helps.