Đây là code Pascal mà em đã làm từ lâu nhưng cũng không động đến nên chưa chuyển sang C được. Các bác tham khảo nhé.
Program DET;
uses crt,sysutils;
label loop,start,finish;
var a:array[1..100,1..100] of real;
t: double;
m,n,i,yy,mm,dd:word;
kt,_loop:byte;
f:text;
key:char;
c:integer;
{ * c: bien luu cap ma tran
* m,n:hang va cot, dung de truot khi nhap va xu ly
* i:index, co su dung o vi tri khu 0
* kt:kiem tra
}
Begin
START:
//Tao file text luu ma tran va dinh thuc da nhap
Decodedate(date,yy,mm,dd);
assign(f,'LogMatrix.txt');
{$I-}
Append(f);
{$I+}
If IOresult<>0 then
Begin
Rewrite(f);
Writeln(f,'This text is created by Matrix.exe');
Writeln(f,' +------------------------------------------------+');
Writeln(f,' | Matrix determinant |');
Writeln(f,' | |');
Writeln(f,' | Dinh thuc ma tran |');
writeln(f,' +------------------------------------------------+'#10#13);
Writeln(f);
Writeln(f,dd,'/',mm,'/',yy,' ',TimeToStr(time));
Writeln(f);
End
Else
Begin
Writeln(f,'====================================================');
Writeln(f);
Writeln(f,dd,'/',mm,'/',yy,' ',TimeToStr(time));
Writeln(f);
End;
//Nhap cap ma tran
Clrscr;
_loop:=0;
Writeln(' +------------------------------------------------+');
Writeln(' | Matrix determinant | Press Ctrl+C');
Writeln(' | | to exit');
Writeln(' | Dinh thuc ma tran |');
writeln(' +------------------------------------------------+'#10#13);
Write(' Nhap cap Ma tran: ');
Readln(c);
If c<0 then
begin
writeln;
writeln('O^ Mai Buoi?. Di ho?i CAVE xem co/ ma tra^n ca^p ',c,' ko nhe/ . -_-');
goto finish;
end;
If c=0 then
begin
writeln;
writeln('Ma tra^n ca^p "O" .XXX. ma`y tha^y so^ ma`y vua` nha^.p gio^ng ca/i do/ ko??. :D');
Writeln('Ca/i ma tra^n na`y kho^ng ti/nh duo.c da^u :v :v :v');
goto finish;
end;
If c=1 then
Begin
writeLN('Dinh thuc cua ma tran cap 1 chinh bang phan tu duy nhat cua no');
goto finish;
End;
If c>100 then
Begin
writeln;
writeln('O^ Mai Chuo^i/... phie^n ba?n sau se~ co/ ma tra^.n ca^p ',c,' :v :v :v');
goto finish;
End;
{=================================================================}
//*** Nha Ma tran, in ra ma tran vua nhap.***
Writeln;
Writeln('*** Cac luu y khi nhap Ma tran:');
writeln(' +===========================================================+');
Writeln(' |* Cac so trong mot hang cach nhau boi dau cach "space" |');
Writeln(' | |');
Writeln(' |* Ket thuc mot hang bang cach go "Enter" |');
Writeln(' | |');
Writeln(' |* Noi dung Ma tran va dinh thuc duoc luu vao LogMatrix.txt |');
Writeln(' | |');
Writeln(' |* Nhan Ctrl+C de thoat chuong trinh bat ky luc nao |');
Writeln(' | |');
Writeln(' |* Cac so nhap thua o 1 hang se duoc day xuong cac vi tri |');
Writeln(' | dau cua hang tiep theo |');
writeln(' +===========================================================+');
Writeln;
Writeln(' +-----------------+');
writeln(' | Ma Tran cap ',c:3,' |');
Writeln(' +-----------------+');
For m:=1 to c do
Begin
Writeln;
Write('Hang ',m,' : ');
For n:=1 to c do
Read(a[m,n]);
End;
//Clrscr;
//Writeln('So lieu xuat ra:');
Writeln;
Writeln('-------------------------');
for i:=1 to (((c*7)div 2)-5)do
Begin
write(' ');
write(f,' ');
End;
Begin
Writeln('Ma tran cap ',c);
Writeln(f,'Ma tran cap ',c);
End;
Write('+-');for i:=1 to (7*c) do write(' ');writeln('-+');
Write(f,'+-');for i:=1 to (7*c) do write(f,' ');writeln(f,'-+');
For m:=1 to c do
Begin
Write('|');Write(f,'|');
For n:=1 to c do
Begin
write(a[m,n]:7:2);
write(f,a[m,n]:7:2);
end;
Writeln(' |'); Write('|'); for i:=1 to (c*7+2) do write(' ');writeln('|');
Writeln(f,' |'); Write(f,'|'); for i:=1 to (c*7+2) do write(f,' ');writeln(f,'|');
// Writeln('----+----+----+-----');
end;
Write('+-');for i:=1 to (7*c) do write(' ');writeln('-+'#10#13);
Write(f,'+-');for i:=1 to (7*c) do write(f,' ');writeln(f,'-+'#10#13);
{==================================================================}
//Khu so 0 o duong cheo chinh.
LOOP: {Dat nhan danh dau}
_loop:=_loop+1;
If _loop=200 then
BEGIN
WriteLN('Loop failure. Please contact to the Programer.');
Write('Press any key to exit');
Exit;
End;
kt:=1; {bien kiem tra xem Ma tran co phan tu 0 hay ko,
neu co kiem tra xem co khu duoc theo hang hay ko,
Co tra ve 1, ko tra ve 0}
For i:=1 to c do
If a[i,i]=0 then
Begin
n:=0;
kt:=0;
Repeat
n:=n+1;
if a[i,n]<>0 then
Begin
kt:=1;
For m:=1 to c do
a[m,i]:=a[m,i]+a[m,n];
End;
Until ((kt=1) or (n=c));
end;
//Dung thuat toan kien tra 1 phan tu o tren duong cheo cua Ma tran co bang 0
//hay ko. Neu no bang 0, tim cac phan tu trong hang tuong ung voi phan tu do
//xem co phan tu nao khac 0 hay ko, neu co, cong cot cua phan tu tim duoc vao
//cot cua phan tu nam tren truc chinh, cho kt=1. Neu khong tim duoc phan tu
//nao thi gan cho kt=0 (bien kiem tra de suy ra DetA=0 neu co mot hang ma tran
//bang 0
{==================================================================}
//in ra Ma tran da khu so 0 o duong cheo chinh
{
If kt=1 then
BEGIN
Writeln('Ma tran sau khi khu 0 o duong cheo chinh:');
Writeln('------------------------------------------');
Writeln;
For m:=1 to c do
Begin
For n:=1 to c do
write(a[m,n]:7:2);
Writeln;
Writeln;
// Writeln('----+----+----+-----');
end;
Writeln('------------------------------------------'#10#13);
END; }
{==================================================================}
//*** Xu ly Ma tran. ***
If kt=1 then
For i:=1 to c do
For m:=i+1 to c do
Begin
IF a[i,i]<>0 then
begin
t:=(-a[m,i]/a[i,i]);
For n:=i to c do
a[m,n]:=a[m,n]+a[i,n]*t;
If a[m,m]=0 then goto loop;
end;
End;
//Muc dich dua ma tran ve tam giac
//Kiem tra kt=1 thi thuc hien buoc nay de tranh truong hop chi cho 0
//Cho i lap tu 1 -> c de chay phan tu tren truc chinh a[i,i]
//Cho m lap tu i+1 -> c de xu ly hang thu (i+1->c)
//Tinh t=(-a[m,i]/a[i,i]) de tim ra so cong vao lam so hang dau cua hang ma
//tran bang 0.
{===================================================================}
//In ra ma tran da dua ve dang tam giac
{
If kt=1 then
BEGIN
Writeln('Ma tran da dua ve tam giac: ');
Writeln('------------------------------');
For m:=1 to c do
Begin
For n:=1 to c do
write(a[m,n]:7:2);
Writeln;
Writeln;
End;
Writeln('------------------------------'#10#13);
END; }
{====================================================================}
//Tinh dinh thuc bang cach nhan cac phan tu cheo
If kt=1 then {kt=1, ma tran da qua cac buoc tren}
BEGIN
t:=1;
For i:=1 to c do
t:=t*a[i,i];
End
Else t:=0; {Neu kt=0 thi DetA=0}
{====================================================================}
Write('DetA= ',t:1:4); //In ra dinh thuc
Writeln(f,'DetA= ',t:1:4);
Readln;
FINISH:
Close(f);
Writeln(#10#13#10#13'--------------------------------');
Writeln(#10#13'Press "E" to exit, any key to continue . . .');
key:=readkey;
If (key<>'E')and(key<>'e') then goto start;
End.
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