Lab 2-4: 大正實數加法 (10%)

  • 輸入：兩正實數的整數部分、正實數的小數部分（輸入數字乘以\( \frac{1}{1,000,000,000,000,000,000} \)），整數及小數各不超過 18 位數字
  • 輸出：兩正實數數值、兩正實數的和，整數不超過 19 位數字，小數部分固定顯示 18 位。
  • 檔名：lab2_4_<學號>.cpp (e.g. lab2_4_106062802.cpp)

程式需提示使用者輸入兩正實數的整數部分、正實數的小數部分，程式需輸出兩正實數數值、兩正實數的和。

Format

Input real number (a), before decimal point: <(a) before decimal point>⏎
Input real number (a), after decimal point: <(a) after decimal point>⏎
The real number (a) is: <real number (a)>
Input real number (b), before decimal point: <(b) before decimal point>⏎
Input real number (b), after decimal point: <(b) after decimal point>⏎
The real number (b) is: <real number (b)>
(a) + (b) = <real number (a) + (b)>

Example

$ ./a.out
Input real number (a), before decimal point: 123456789012345678⏎
Input real number (a), after decimal point: 123456789012345678⏎
The real number (a) is: 123456789012345678.123456789012345678
Input real number (b), before decimal point: 987654321098765432⏎
Input real number (b), after decimal point: 987654321098765432⏎
The real number (b) is: 987654321098765432.987654321098765432
(a) + (b) = 1111111110111111111.111111110111111110

$ ./a.out
Input real number (a), before decimal point: 1⏎
Input real number (a), after decimal point: 1⏎
The real number (a) is: 1.000000000000000001
Input real number (b), before decimal point: 2⏎
Input real number (b), after decimal point: 2⏎
The real number (b) is: 2.000000000000000002
(a) + (b) = 3.000000000000000003

Reference:

Reference Code:

Credit: 金昆樂 (110021111)

#include <iostream>
#include <iomanip>
#include <cmath>
using namespace std;
int main()
{
    long long int a1 = 0, a2 = 0, b1 = 0, b2 = 0;
    cout << "Input real number (a), before decimal point: ";
    cin >> a1;
    cout << "Input real number (a), after decimal point: ";
    cin >> a2;
    cout << "The real number (a) is: " << a1 << "."
         << setfill('0') << setw(18) << a2 << endl;
    cout << "Input real number (b), before decimal point: ";
    cin >> b1;
    cout << "Input real number (b), after decimal point: ";
    cin >> b2;
    cout << "The real number (b) is: " << b1 << "."
         << setfill('0') << setw(18) << b2 << endl;
    long long int c2 = a2 + b2, c1 = a1 + b1;
    long long int N = 1000000000000000000;
    if (c2 >= N)
    {
        c2 = c2 - N;
        c1++;
    }
    cout << "(a) + (b) = " << c1 << '.'
         << setfill('0') << setw(18) << c2 << endl;
    return 0;
}