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  1. #include <iostream>
  2. #include <vector>
  3. #include <string>
  4. #include <sstream>
  5. using std::cout; using std::cin; using std::cerr; using std::endl;
  6. using std::vector; using std::string;
  7.  
  8. int main()
  9. {
  10.     string input; // for storing our input in
  11.  
  12.     cout << "Type your calculations, example \"5+5-2*6/4\" (Spaces are allowed) : "; // tell user how the calculator works
  13.     while (getline(cin, input)) { // get inuut
  14.         vector<int> iv; // for holding our numbers that we are going to calculate
  15.         vector<char> cv; // for checking if user wants to +,-,*,/
  16.         if (!input.empty())
  17.         {
  18.             std::istringstream in(input);
  19.  
  20.             while (in)
  21.             {
  22.                 in >> std::ws;  // consume whitespace.
  23.  
  24.                 int value;
  25.                 if (isdigit(in.peek()) && in >> value)
  26.                     iv.push_back(value);
  27.                 else
  28.                 {
  29.                     in.clear();
  30.                     char ch;
  31.                     if (in >> ch)
  32.                     {
  33.                         if (ch == '+' || ch == '-' || ch == '*' || ch == '/')
  34.                             cv.push_back(ch);
  35.                         else
  36.                         {
  37.                             cerr << "Sorry character/sign not known: '"
  38.                                 << ch << "'. Only +,-,*,/.\n";
  39.                             return -1;
  40.                         }
  41.                     }
  42.                 }
  43.             }
  44.  
  45.             int answer = 0, counter = 0; // For holding the answer
  46.             auto cvcbegin = cv.cbegin(), cvcend = cv.cend();
  47.             while (cvcbegin != cvcend) {
  48.                 while (*cvcbegin == '+') {
  49.                     if (counter == 0) {
  50.                         answer = iv[0] + iv[1];
  51.                         cout << iv[0] << " + " << iv[1] << " = " << answer << endl;
  52.                         counter = 2;
  53.                         ++cvcbegin;
  54.                     }
  55.                     else {
  56.                         cout << answer << " + " << iv[counter] << " = " << answer + iv[counter] << endl;
  57.                         answer = answer + iv[counter];
  58.                         ++counter;
  59.                         ++cvcbegin;
  60.                     }
  61.                 }
  62.                 while (*cvcbegin == '-') {
  63.                     if (counter == 0) {
  64.                         answer = iv[0] - iv[1];
  65.                         cout << iv[0] << " - " << iv[1] << " = " << answer << endl;
  66.                         counter = 2;
  67.                         ++cvcbegin;
  68.                     }
  69.                     else {
  70.                         cout << answer << " - " << iv[counter] << " = " << answer - iv[counter] << endl;
  71.                         answer = answer - iv[counter];
  72.                         ++counter;
  73.                         ++cvcbegin;
  74.                     }
  75.                 }
  76.                 while (*cvcbegin == '*') {
  77.                     if (counter == 0) {
  78.                         answer = iv[0] * iv[1];
  79.                         cout << iv[0] << " * " << iv[1] << " = " << answer << endl;
  80.                         counter = 2;
  81.                         ++cvcbegin;
  82.                     }
  83.                     else {
  84.                         cout << answer << " * " << iv[counter] << " = " << answer * iv[counter] << endl;
  85.                         answer = answer * iv[counter];
  86.                         ++counter;
  87.                         ++cvcbegin;
  88.                     }
  89.                 }
  90.                 while (*cvcbegin == '/') {
  91.                     if (counter == 0) {
  92.                         answer = iv[0] / iv[1];
  93.                         cout << iv[0] << " / " << iv[1] << " = " << answer << endl;
  94.                         counter = 2;
  95.                         ++cvcbegin;
  96.                     }
  97.                     else {
  98.                         cout << answer << " / " << iv[counter] << " = " << answer / iv[counter] << endl;
  99.                         answer = answer / iv[counter];
  100.                         ++counter;
  101.                         ++cvcbegin;
  102.                     }
  103.                 }
  104.             }
  105.             cout << "\nAgain?\n" << endl;
  106.         }
  107.         else { // If we get no input then...
  108.             cerr << "No input, well bye." << endl; // Tell user that there was no input
  109.             return -1; // return failiure
  110.         }
  111.     }
  112.     return 0;
  113. }
Success #stdin #stdout 0s 3440KB
comments (?)
stdin
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10+5
stdout
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Type your calculations, example "5+5-2*6/4" (Spaces are allowed) : 10 + 5 = 15

Again?
https://ideone.com/HZovSP
language:
C++14 (gcc 8.3)
created:
10 years ago
visibility:
secret

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