輸入解析問題

Question

當用戶在數字之間輸入空格以創建引用字符串時，它會拋出所有內容，甚至會將數字帶到下一個cin。但是，如果他們之間有字母而沒有空格，它可以正常工作。該作業是爲了換頁模擬。

代碼（這是應該影響我的問題的代碼只是一部分）：

void main() 
{ 
    bool again = false; 
    bool reuse = false; 
    bool valid; 
    int use; 
    int refLength; 
    vector<int> ref(0); 
    vector<frame> frames(0); 
    string refString; 
    string user; 

    //ask how long the user wants the ref string to be 
    do{ 
     valid = false; 
     while (!valid&&!reuse)//take choice of ref string 
     { 
      cout << "How long do you wish the reference string to be? "; 
      if (!(cin >> refLength)) 
      { 
       cin.clear();//.clear and .ignore keep cin from errors and forced infinite loop repeating following cout 
       cin.ignore(numeric_limits<streamsize>::max(), '\n'); 
       cout << "The length must be enter as an integer value between "; 
       valid = false; 

      } 

      else 
      { 
       cout << "You have chosen to have a Ref string of " << refLength << " length " << endl; 
       valid = true; 
      } 
     } 
     valid = false; 

     while (!valid&&!reuse) 
     { 
      cout << "Do you want to enter a ref string or randomly generate one" << endl; 
      cout << "of your chosen length? Enter 1 to generate and 2 to input the string "; 
      if (!(cin >> use) | (use<0 || use>2)) 
      { 
       cin.clear();//.clear and .ignore keep cin from errors and forced infinite loop repeating following cout 
       cin.ignore(numeric_limits<streamsize>::max(), '\n'); 
       cout << "You must enter an integer between 1 and 2"; 

      } 
      else 
      { 
       valid = true; 
       if (use == 1) 
       { 
        make(ref, refLength); 
       } 
       else 
       { 
        cout << "please enter a ref string of chosen length entering" << endl; 
        cout << "fewer digits will cause 0's to be added. Entering more" << endl; 
        cout << "will cause those past the chosen length to be dropped " << endl; 
        cout << "any letters will be ignored but spaces throw things off" << endl; 
        cout << "Also all entries must be single digit integers (0-9) " << endl; 
        cin >> refString; 
        make(ref, refLength, refString); 
       } 
       use = 0; 
      } 

     } 
     cout << endl; 
     /*for(int i=0;i<ref.size();i++) 
     { 
     cout<<ref[i]<<" "; 
     }*/ 
     valid = false; 
     while (!valid) 
     { 
      cin.clear(); 
      //errors ********************************************88 
      cout << "How many frames do you want (1-7) "; 
      if (!(cin >> use) | (use<0 || use>7)) 
      { 
       cin.clear(); 
       cin.ignore(numeric_limits<streamsize>::max(), '\n'); 
       cout << "You must enter an integer between 1 and 7 "; 
       valid = false; 
      } 
      else 
      { 
       valid = true; 
       setUpFrames(use, frames); 
       use = 0; 
      } 
     } 
     valid = false; 
     while (!valid) 
     { 
      cout << "Enter 1 for FIFO or 2 for LRU pageRep algo or 3 for Optimal"; 

      if (!(cin >> use) | (use<0 || use>3)) 
      { 
       cin.clear(); 
       cin.ignore(numeric_limits<streamsize>::max(), '\n'); 
       cout << "Must be int between 1 and 3"; 
      } 
      else if (use == 1) 
      { 
       cout << endl << "# of Page Faults "; 
       cout << FIFO(ref, frames); 
       valid = true; 
      } 
      else if (use == 2) 
      { 
       cout << endl << "# of Page Faults "; 
       cout << LRU(ref, frames); 
       valid = true; 
      } 
      else 
      { 
       cout << endl << "# of Page Faults "; 
       cout << Optimal(ref, frames); 
       valid = true; 
      } 

     } 
     cout << endl; 
     cout << "do you want to try again ? Enter y for yes anything else for no" << endl; 
     cin >> user; 
     if (user == "y") 
     { 
      again = true; 
      cout << "do you want to use the same reference string? y for yes anything else for no" << endl; 
      cin >> user; 
      if (user == "y") 
      { 
       reuse = true; 
      } 
      else 
      { 
       reuse = false; 
      } 
     } 
     else 
     { 
      again = false; 
     }  
    } while (again);  
} 

Answer 1

如果您想通過字/行使用函數getline CIN/COUT互動字/行，否則混亂將會出現。