gaussian

Numerical Methods- Gauss Elimination

#include<iostream>
using namespace std;
#include"MathFunc.cpp"
#include<time.h>

int main()
{	
	int n;    
    	cout<<"Enter number of unknown variable : ";  
    	cin>>n;
	long double *mat = new long double[n*n];
	long double *b = new long double[n]; 
	getMatrix(mat,b,n);
        //getInput("d_49_49","fx_49",mat,b,n);
        //getInput("D_225_225","fx_225",mat,b,n);
        //getInput("input.txt","input1.txt",mat,b,n);
        //getSparseInput("matrxi_2304","rhsvect_2304",mat,b,n);       
        dispMatrix(mat,b,n); 
	long double *determinant = new long double[n]; 	
        for(int i=0; i<n; i++)
              *(determinant+i) = 1;
	long double dtrmnt=1;
	int g=0;
        long double *x = new long double[n]; 
	for(int i=0; i<n; i++)
	{
		if(*(mat+i*n+i))
		{			
			long double leadvar=*(mat+i*n+i);
			*(determinant+(g++))=leadvar;
			for(int j=0; j<=n; j++)
			{
				if(j < n)
					*(mat+i*n+j)=(*(mat+i*n+j))/leadvar;
				else
					*(b+i)=(*(b+i))/leadvar;
			 }			
			for(int j=i+1; j<n; j++)
			{
				long double conzero = *(mat+j*n+i);
				for(int k=0; k<=n; k++)
				{
					if(k < n)
					    *(mat+j*n+k)=(*(mat+j*n+k))-(conzero)*(*(mat+i*n+k));
					else
					    *(b+j)=(*(b+j))-(conzero)*(*(b+i));
				}
			}
		}
		else
		{                   
		   *(determinant+(g++))=-1;
                   long double t;
		   for(int t1=i+1; t1<n; t1++)
		   {
		       if(*(mat+i*n+t1))
		       {
			   for(int m1=0; m1<=n; m1++)
			   {
				if(m1 < n)
                        	{
				    t = *(mat+i*n+m1);
				    *(mat+i*n+m1)=(*(mat+t1*n+m1));
                                    *(mat+t1*n+m1) = t;
				}
				else
                                {
				    t = *(b+i);
				    *(b+i)=*(b+t1);
				    *(b+t1) = t;
				}
			   }

			}
		    }                    
		}                
	}

	for(int i=0; i<n; i++)
		*(determinant+(g++))=*(mat+i*n+i);

	for(int i=0; i<g; i++)
		dtrmnt*=(*(determinant+i));

	cout<<"Matrix in Trianguler form is :"<<endl;	
	dispMatrix(mat,b,n);	       	
	calX(x,mat,b,n);	
	dispX(x,n);
	cout<<"Determinant of given matrix: "<<dtrmnt<<endl;
        
	return 0;
}