Pascal高精度加减乘除代码

以下是一个示例的Pascal代码，展示了如何实现高精度的加减乘除运算：

program HighPrecisionCalc;

uses
  SysUtils;

type
  BigNumber = array of Integer;

// 将字符串转换为大数表示
function StrToBigNumber(s: string): BigNumber;
var
  i: Integer;
begin
  SetLength(Result, Length(s));
  for i := 1 to Length(s) do
    Result[Length(s)-i+1] := Ord(s[i]) - Ord('0');
end;

// 将大数表示转换为字符串
function BigNumberToStr(num: BigNumber): string;
var
  i: Integer;
begin
  Result := '';
  for i := Length(num) downto 1 do
    Result := Result + Chr(num[i] + Ord('0'));
end;

// 大数加法
function Add(a, b: BigNumber): BigNumber;
var
  carry, i, sum: Integer;
begin
  carry := 0;
  SetLength(Result, Max(Length(a), Length(b)) + 1);
  for i := 0 to Max(Length(a), Length(b)) do
  begin
    sum := carry;
    if i < Length(a) then
      sum := sum + a[i];
    if i < Length(b) then
      sum := sum + b[i];
    Result[i] := sum mod 10;
    carry := sum div 10;
  end;
end;

// 大数减法
function Subtract(a, b: BigNumber): BigNumber;
var
  borrow, i, diff: Integer;
begin
  borrow := 0;
  SetLength(Result, Max(Length(a), Length(b)));
  for i := 0 to Max(Length(a), Length(b))-1 do
  begin
    diff := borrow + a[i];
    if i < Length(b) then
      diff := diff - b[i];
    if diff < 0 then
    begin
      borrow := -1;
      diff := diff + 10;
    end
    else
      borrow := 0;
    Result[i] := diff;
  end;
end;

// 大数乘法
function Multiply(a, b: BigNumber): BigNumber;
var
  i, j, carry, prod: Integer;
begin
  SetLength(Result, Length(a) + Length(b));
  for i := 0 to Length(a)-1 do
  begin
    carry := 0;
    for j := 0 to Length(b)-1 do
    begin
      prod := Result[i+j] + a[i] * b[j] + carry;
      Result[i+j] := prod mod 10;
      carry := prod div 10;
    end;
    Result[i+Length(b)] := carry;
  end;
end;

// 大数除法
function Divide(a: BigNumber; b: Integer): BigNumber;
var
  i, remainder, quotient: Integer;
begin
  SetLength(Result, Length(a));
  remainder := 0;
  for i := Length(a)-1 downto 0 do
  begin
    remainder := remainder * 10 + a[i];
    quotient := remainder div b;
    remainder := remainder mod b;
    Result[i] := quotient;
  end;
end;

var
  num1, num2: string;
  a, b, sum, diff, product, quotient: BigNumber;
  divisor: Integer;

begin
  Write('输入第一个大数：');
  Readln(num1);
  Write('输入第二个大数：');
  Readln(num2);
  Write('输入除数：');
  Readln(divisor);

  a := StrToBigNumber(num1);
  b := StrToBigNumber(num2);

  sum := Add(a, b);
  diff := Subtract(a, b);
  product := Multiply(a, b);
  quotient := Divide(a, divisor);

  Writeln('加法结果：', BigNumberToStr(sum));
  Writeln('减法结果：', BigNumberToStr(diff));
  Writeln('乘法结果：', BigNumberToStr(product));
  Writeln('除法结果：', BigNumberToStr(quotient));
  
end.

这个示例程序可以实现大数的加减乘除运算。您可以根据自己的需求进行修改和扩展。使用StrToBigNumber函数将字符串转换为大数表示，然后使用Add、Subtract、Multiply和Divide函数进行相应的运算，最后使用BigNumberToStr函数将结果转换回字符串形式输出。