"Top triangle" determine the source code (improved version, added special processing in several special cases)

# Include <iostream. h>
# Include <fstream. h>
# Include <cmath>
Void main ()
{
// Start with the input deciding factor
Int n, I, j, a [20] [20], T [20], max [20], B [20], k, q, p, f = 2, u = 0;
Float t [20] [20], c, sum = 1, w [20];
Cout <"order :";
Cin> n;
Ifstream infile; // defines the input file class.
Ofstream outfile; // defines the output file class.
Infile. open ("D: \ exam question .txt"); // open an input file: exam question .txt"
For (I = 1; I <= n; I ++)
{
For (j = 1; j <= n; j ++)
{
Infile> a [I] [j]; // input the ten integer numbers in the "exam question .txt" to a [I ].
}
}
Infile. close (); // close the input file
// Enter the rank of the determinant
For (j = 1; j <= n; j ++) // start from the first column.
{
T [j] = 0; // initializes the counter to 0
For (I = 1; I <= n; I ++)
{
If (a [I] [j] = 0) // count every 0 found in column j
{
T [j] ++; // counts the number of zeros in column j.
}
}
}
Outfile. open ("D: \ .txt"); // open an output file and click ".txt"
// After the loop ends, the number of zeros in each column is stored in the array T [j ].
// Start to compare the number of zeros in each column and arrange them
For (I = 1; I <= n; I ++) // sort T [j] in ascending order after n cycles
{
Max [I] =-100;
For (j = 1; j <= n; j ++)
{
Max [I] = (max [I]> T [j])? Max [I]: T [j];
}
// Find the maximum I value
For (j = 1; j <= n; j ++) // find the number of columns corresponding to the maximum I value through a loop j is the corresponding number of Columns
{
If (max [I] = T [j])
{
T [j] =-200; // set T [j] to a smaller number.
// Outfile <"th" <j <"column:" <max [I] <"0" <endl;

B [I] = j;
Break;
}
}
}
Outfile <"------------------------------------ determine the answer -------------------------------------" <endl;
// Print New Determinant
Outfile <"Step 1: Change columns:" <endl;
For (I = 1; I <= n; I ++)
{
For (j = 1; j <= n; j ++)
{
T [I] [j] = float (a [I] [B [j]);
// Determine the number of change Columns
If (I = 1 & j! = B [j])
{
U ++;
}
Outfile <t [I] [j] <"";
}
Outfile <endl;
}
// Solution to the special case where the first number is 0
If (t [1] [1] = 0)
{
For (I = 2; I <= n; I ++)
{
If (t [I] [1]! = 0)
{
For (j = 1; j <= n; j ++)
{
W [j] = t [I] [j];
T [I] [j] = t [1] [j];
T [1] [j] = w [j];
}
Break;
}
}
U ++;
}
// After changing the column, store the new determinant in a new array t [] []
For (j = 1; j <n; j ++) // Column
{
For (k = j + 1; k <= n; k ++) // The row whose column j needs to be converted to 0
{
If (t [k] [j]! = 0)
{
For (I = j; I <= n; I ++) // line
{
If (t [I] [j]! = 0 & I! = K)
{
P = 0;
C = float (t [k] [j]/t [I] [j]);
For (q = 1; q <= n; q ++) // Column
{
T [k] [q] = t [k] [q]-c * t [I] [q];
If (abs (t [k] [q]) <0.0001 & k! = Q)
{
T [k] [q] = 0;
}
P ++;
}
// Print the intermediate process
Outfile <"Step" <f ++ <: r ["<k <"]-"<c <" r ["<I <"]: "<endl;
For (int s = 1; s <= n; s ++)
{
For (int d = 1; d <= n; d ++)
{
Outfile <t [s] [d] <"";
}
Outfile <endl;
}
If (p = n)
{
Break;
}
}
}
}
}
}
For (I = 1; I <= n; I ++)
{
Sum = t [I] [I] * sum;
}
Outfile <"no." <f ++ <"step:" <endl;
If (u! = 0)
{
U = U-1;
}
Outfile <"final result =" <sum * pow (-1, u) <endl;
Outfile. close (); // close the output file

 

}