#include "conio.h"
#include "iostream.h"
#define max 100
//Nhap ma tran tam giac tren
void Nhap(float A[max][max],int n) {
for(int i = 0; i<n; i++)
for(int j = i; j<n; j++) {
cout<<"a["<<i<<"]["<<j<<"] = ";
cin>>A[i][j];
}
}
/*Nhap ma tran he so tu do*/
void Nhap(float B[max],int n) {
for(int i = 0; i<n; i++) {
cout<<"b["<<i<<"] = ";
cin>>B[i];
}
}
/*Xuat ma tran he so tu do*/
void Xuat(float B[max],int n) {
cout<<"(";
for(int i = 0; i<n-1; i++)
cout<<B[i]<<",";
cout<<B[n-1]<<")";
}
/*Xuat ma tran*/
void Xuat(float A[max][max], int n) {
cout<<"\n";
for(int i=0 ; i<n; i++){
cout<<endl;
for(int j=0 ; j<n; j++)
if(i>j)
cout<<"0\t";
else
cout<<A[i][j]<<"\t";
}
}
/*Xuat nghiem*/
void XuatNghiem(float X[], int n, char * s) {
cout<<"\nNghiem cua he A.X = B\n";
for(int i=0; i<n; i++)
cout<<s<<i+1<<" = "<<X[i]<<endl;
}
/*He tam giac tren*/
char HeTamGiacTren (float A[max][max], float X[max], float B[max], int n ) {
for(int i = n-1; i>=0; i--) {
if (A[i][i]!=0) {
if (i==n-1)
X[i] = B[i]/A[i][i];
else {
X[i] = B[i];
for(int j=i+1; j<n; j++)
X[i]=X[i]-A[i][j]*X[j];
X[i] = X[i]/A[i][i];
}
}
else
return 0;
}
return 1;
}
/*Chuong trinh chinh*/
void main() {
int n;
float A[max][max],B[max],X[max];
clrscr();
cout<<"So phuong trinh n = ";
cin>>n;
cout<<"Nhap vao ma tran tam giac tren A\n";
Nhap(A,n);
cout<<"\nNhap vao ma tran he so B\n";
Nhap(B,n);
clrscr();
cout<<"Ma tran A";
Xuat(A,n);
cout<<"\nMa tran B\n";
Xuat(B,n);
if(HeTamGiacTren(A,X,B,n))
XuatNghiem(X,n,"x");
else
cout<<"\nHe phuong trinh tuyen tinh vo nghiem";
getch();
}