一个简单的加法、减法、乘法和除法程序 一个简单的C++计算器程序，计算加法、减法、乘法和加法……/P> #include <iostream> #include <string> using namespace std; int main() { //input declarations as doubles for total and counter double total = 0, counter =0; //input declarations sign and Q as character char sign, Q = 0; //input declaration value as double double value; //A do..while will loop forever (or until we hit the break statement) do { //The current value is 0. cout << "Result :"<<" "<< total << '\n'; //Please enter an operation cout << "Please enter an operation and number : "; cin >> sign; //If the operation is Q, the program will end. if (sign != 'Q') cin >> value; cin.ignore(); // If the value input is <=0, you can't divide anything by zero. if (value <= 0) { cout << "Unknown Operator " << sign <<'\n' ; } //Otherwise procede with the calulator program else { //If the operation is equal to '+', then the total is added. if (sign == '+') { total += value; } // If the operation is equal to '-', then the value is subtracted from the previous number input. else { if (sign == '-') { total -= value; } // If the operation is equal to '*', then the value is multiplied to the previous number input. else { if (sign == '*') { total *= value; } // If the operation is equal to '/', then the value is divided by the previous number input. else { if ((sign == '/')&&(value != 0)) { total /= value; } } } } } } //While the operation is not equal to 'Q', the program will run. while (sign != 'Q'); return 0; } #包括 #包括 使用名称空间std； int main（） { //输入声明为total和counter的两倍 双倍合计=0，计数器=0； //输入声明符号和Q作为字符 字符符号，Q=0； //以双精度输入声明值 双重价值； //A do..while将永远循环（或直到我们到达break语句） 做 { //当前值为0。 不能包含 双结果=sqrt（值）；

将

if（sign！=“Q”）替换为
if（sign==“Q”）中断；


这将修复许多可能的错误
这将通过使用更少的缩进和大括号使代码更具可读性

编辑：正如有人提到的，您可能也应该检查小写。（如果（sign='Q'| | sign='Q'）。
表示平方根，
#包括
双r=sqrt（e）；

关于您的其他问题：请更好地缩进代码；-）

你确定你没有忘记在这条线后面加一个方块吗？
if（sign！=“Q”）

最简单的方法，在步骤模式中使用调试器，你会理解！
作为一个简单的练习，我已经重构了你的程序，使它更简单。我不保证它是有效的，但是它应该给你一个很好的基础来建立：
#include <iostream>
#include <string>
using namespace std;

int main()
{
  //input declarations as doubles for total and counter
  double total = 0, counter =0;
  //input declarations sign and Q as character
  char sign = 0;
  //input declaration value as double
  double value;

  //A do..while will loop forever (or until we hit the break statement)
  do 
  {
    //The current value is 0.
    cout << "Current result: " << total << '\n';

    //Please enter an operation
    cout << "Please enter an operation (or Q to quit) and number: ";
    cin >> sign;

    //If the operation is Q, the program will end.
    if (sign == 'Q' || sign == 'q') {
      cout << "See you!\n";
      break;
    }

    // If the input cannot be transformed into a double
    // abort loop and try again
    if (!(cin >> value)) {
      cerr << "Invalid value entered, try again\n";
      continue;
    }

    switch(sign)
    {
    case '+': total += value; break;
    case '-': total -= value; break;
    case '*': total *= value; break;
    case '/':
      if (value == 0) {
        cerr << "Divide by 0 prevented!\n";
      } else {
        total /= value; break;
      }
    default:
      cerr << "Unknown sign: " << sign << "\n";
    }

  } while (true);

  return 0;
}

#包括
#包括
使用名称空间std；
int main（）
{
//输入声明为total和counter的两倍
双倍合计=0，计数器=0；
//输入声明符号和Q作为字符
字符符号=0；
//以双精度输入声明值
双重价值；
//A do..while将永远循环（或直到我们到达break语句）
做
{
//当前值为0。
CUT“上面的程序编码没有错误”，你按下“Q”还是“Q”。你的代码只检查“Q”，我按下“Q”，程序没有退出。谢谢方根代码。你说的是在行之后加块？什么意思？对不起，我只是初学者，所以我不熟悉所有的C++术语。在测试之后，把一个显式的块{}，这很有帮助。由于你的代码有奇怪的缩进，这将提高可读性。噢，非常感谢。你的程序非常简单。我真的很感激！！！
#include <iostream>
#include <string>
using namespace std;

int main()
{
  //input declarations as doubles for total and counter
  double total = 0, counter =0;
  //input declarations sign and Q as character
  char sign = 0;
  //input declaration value as double
  double value;

  //A do..while will loop forever (or until we hit the break statement)
  do 
  {
    //The current value is 0.
    cout << "Current result: " << total << '\n';

    //Please enter an operation
    cout << "Please enter an operation (or Q to quit) and number: ";
    cin >> sign;

    //If the operation is Q, the program will end.
    if (sign == 'Q' || sign == 'q') {
      cout << "See you!\n";
      break;
    }

    // If the input cannot be transformed into a double
    // abort loop and try again
    if (!(cin >> value)) {
      cerr << "Invalid value entered, try again\n";
      continue;
    }

    switch(sign)
    {
    case '+': total += value; break;
    case '-': total -= value; break;
    case '*': total *= value; break;
    case '/':
      if (value == 0) {
        cerr << "Divide by 0 prevented!\n";
      } else {
        total /= value; break;
      }
    default:
      cerr << "Unknown sign: " << sign << "\n";
    }

  } while (true);

  return 0;
}