读取含行列数的文本文件并构建矩阵的技术实现咨询

Absolutely, your requirement is totally achievable! Let's first break down the issues in your current code, then walk through a corrected version that meets your needs perfectly.

What's Off With Your Existing Code? #

• The while not eoln(datoteka) loop keeps reading values into m and n until the end of the first line. This means by the loop's end, m and n will get overwritten to the last two numbers in the line (instead of the first two, which are your intended row and column counts).
• The repeat-until block has invalid Pascal syntax (read eoln(n) isn't a valid statement) and no logical purpose for reading matrix elements.
• There’s no code to actually construct or populate the matrix, and you never close the file—this is a basic best practice to avoid resource leaks.

Corrected Pascal Code #

Here’s a fully functional version that reads the matrix dimensions and populates the matrix correctly:

Program MatrixBuilder;
const MAX_SIZE = 100; // Clearer constant name for maximum matrix size
type Matrix = array[1..MAX_SIZE, 1..MAX_SIZE] of Integer;
var
  datoteka: Text;
  m, n: Integer;      // m = rows, n = columns
  i, j: Integer;      // Loop counters for rows and columns
  matrix: Matrix;     // The matrix we'll build
begin
  // Link the file variable to your input file
  Assign(datoteka, 'datoteka.txt');
  Reset(datoteka);
  
  // Step 1: Read the first two values as matrix dimensions (rows m, columns n)
  Read(datoteka, m, n);
  
  // Step 2: Read the next m*n values and populate the matrix row by row
  for i := 1 to m do
    for j := 1 to n do
      Read(datoteka, matrix[i][j]);
  
  // Optional: Print the matrix to verify it's built correctly
  Writeln('Successfully built matrix (', m, ' rows, ', n, ' columns):');
  for i := 1 to m do
  begin
    for j := 1 to n do
      Write(matrix[i][j], ' ');
    Writeln; // New line after each row
  end;
  
  // Always close the file when done
  Close(datoteka);
end.

How It Works With Your Example Input #

For your sample input text: 4 3 1 2 3 5 6 7 9 10 8 1 11 13

• The code first reads m=4 (rows) and n=3 (columns)
• Then it reads the next 4*3=12 values and fills the matrix row by row
• The verification output will be:

Successfully built matrix (4 rows, 3 columns):
1 2 3 
5 6 7 
9 10 8 
1 11 13 

内容的提问来源于stack exchange，提问作者ZoranSRB17