字符串沒有被正確打印/初始化

Question

我一直在Cpp上玩Hang子手遊戲...... 所以我創建了一個名爲SoFar的變量，它在起始處存儲破折號，但是逐漸被發現。

for(i = 0; i <= TheWord.length(); i++) 
      SoFar[i] = '-'; 

所以，我（試圖）初始化SoFar包含在首發破折號，並且具有相同的長度爲TheWord

後來，當我打印SOFAR，它只是空的！

cout << "\nSo far, the word is : " << SoFar << endl; 

任何和所有的建議表示讚賞。這是我的完整方案，以供參考：

#include <iostream> 
#include <cstdlib> 
#include <string> 
#include <vector> 
#include <ctime> 
#include <cctype> 

using namespace std; 

int main() 
{ 

    vector<string> words; 
    words.push_back("SHAWARMA"); 
    words.push_back("PSUEDOCODE"); 
    words.push_back("BIRYANI"); 
    words.push_back("TROLLED"); 
    srand((unsigned)time(NULL)); 
    string TheWord = words[(rand() % words.size()) + 1]; 
    string SoFar;   
    const int MAXTRIES = 8; 
    string used = ""; 
    int tries, i; 
    i = tries = 0; 
    char guess; 
     for(i = 0; i <= TheWord.length(); i++) 
      SoFar[i] = '-'; 

    while(tries <= MAXTRIES && SoFar != TheWord) 
    { 
     /****************************************************************/ 
     /*       I/0         */ 
     /****************************************************************/ 
     cout << "\nYou haz " << MAXTRIES - tries << " tries to go!\n" ; 
     cout << "You've used the following letters : "; 

     for(i = 0; i <= used.length(); i++) 
      cout << used[i] << " : " ; 

     cout << "\nSo far, the word is : " << SoFar << endl; 
     cout << "\nEnter your guess : " ; 
     cin >> guess; 
     /****************************************************************/ 
     /*       Processing input     */ 
     /****************************************************************/ 
     if(used.find(guess) != string::npos) 
      continue; 
     guess = toupper(guess); 
     if(TheWord.find(guess) != string::npos) 
     { 
      for(i = 0; i <= TheWord.length(); i++) 
      { 
       if(guess == TheWord[i]) 
        SoFar[i] = guess; 
      } 

     } 
     else 
     { 
      cout << "\nSorry, but the word doesn't have a letter like " << guess << " in it...\n"; 
      tries++; 
     } 
       used += guess; 

    } 

    if(tries == MAXTRIES) 
     cout << "\nYep, you've been hanged...\n"; 
    else if(SoFar == TheWord) 
     cout << "\nYou got it! Congratulations...\n(Now Im gonna add some psuedorandomly generated words just for you <3 :P)"; 

    cout << "\nThe word was : " << TheWord; 

    return 0; 
} 

Answer 1

您定義SoFar爲：

string SoFar;   

...然後嘗試寫它：

for(i = 0; i <= TheWord.length(); i++) 
     SoFar[i] = '-'; 

當你寫它，SoFar仍具有長度爲0，所以每當你執行SoFar[i] = '-';時，你會得到未定義的行爲。

嘗試：

std::string SoFar(TheWord.length(), '-'); 

這個定義已經包含破折號權數SoFar。

這裏有一個快速演示：

#include <string> 
#include <iostream> 

int main(){ 
    std::string TheWord{"TROLLED"}; 

    std::string SoFar(TheWord.length(), '-'); 

    std::cout << TheWord << "\n"; 
    std::cout << SoFar << "\n"; 
} 

至少對我來說，這似乎產生結果的正確長度：

TROLLED 
------- 

Answer 2

你試圖修改不存在的對象：

string SoFar;   
const int MAXTRIES = 8; 
string used = ""; 
int tries, i; 
i = tries = 0; 
char guess; 
    for(i = 0; i <= TheWord.length(); i++) 
     SoFar[i] = '-'; 

由於SoFar是空的，試圖修改SoFar[i]是不確定的行爲。

Answer 3

您指定的SOFAR爲字符串，因此嘗試使用雙價值報價

for(i = 0; i <= TheWord.length(); i++) 
SoFar[i] = "-";