int m[25][3];

fin >> m[j]; //there IS an error in this line.

//...
fin >> m[j][k];
//...

#include <iostream>
#include <fstream>
#include <cstdlib>
using namespace std;

int main()
{
    char s[30];                 //string to read a line from the file
    int first[10];              //integer arrays to get integers from file
    int second[10];             
    float third[10];            //float arrays go get floatint point numbers from file
    float fourth[10];
    float fifth[10];
    int no_of_lines, j;         //no_of_lines holds the number of lines read from the file
    
    ifstream fin;               //create new inputstream and open file try1.txt
    fin.open("try1.txt");
    
    if (fin.fail())             //check whether there is any error in opening the file
    {
        cout << "ERROR opening file.";
    }
    
    else                        //if there is no error message
    {
        j = 0;                  //initialize counter to 0
            
        while (!fin.eof())      //check whether the end of file is reached.
        {
            fin.getline(s, 30); //get a line from the file
            
            //scan the string s for the integers and floats.
            sscanf(s, "%d %d %f %f %f ", &first[j], &second[j], &third[j], &fourth[j], &fifth[j]);
            
            j++;                //increment the counter j
        }
    }

    no_of_lines = j;            //number of lines is j
    
    //print the results.
    cout<<"The input from the file is.. "<<endl;    
    for( j=0; j < no_of_lines ;j++)
    {
        cout<<first[j]<<" "<<second[j]<<" "<<third[j]<<" "<<fourth[j]<<" "<<fifth[j]<<endl;
    }
    
    cout << endl;
    
    getchar();
    getchar();
    return 0;
    
}