要檢查一個字符串是否具有所有唯一字符在C + +

Question

我試圖找到如果一個字符串具有所有的唯一字符和以下是我的代碼，但我得到錯誤「數組下標」無效類型'char [int]'in函數Unique char的if語句，誰能告訴我如何解決這個問題

#include <iostream> 
#include<cstring> 

using namespace std; 
bool unique_char(char); 

int main() 
{ 
    char s; 
    bool check; 
    cout << "Enter any string" << endl; 
    cin>>s; 
    check = unique_char(s); 
    if(check) 
     cout<<"there are no duplicates"; 
    else 
     cout<<"the string has duplicates"; 

    return 0; 
} 

// The if statement in this section has the error 
bool unique_char(char s) 
{ 
    bool check[256] = {false}; 
    int i=0; 
    while (s != '\0') 
    { 
     if (check **[(int) s[i]]**) 
      return false; 
     else 
     { 
     check[(int) s[i]] = true; 
     i++; 
     } 

    } 
} 

Answer 1

您需要傳遞char數組而不是單個char。

int main() 
{ 
    char s[1000]; // max input size or switch to std::string 
    bool check; 
    cout << "Enter any string" << endl; 
    cin>>s; 
    check = unique_char(s); 
    if(check) 
     cout<<"there are no duplicates"; 
    else 
     cout<<"the string has duplicates"; 

    return 0; 
} 

bool unique_char(char* s) 
{ 
    bool check[256] = {false}; 
    int i=0; 
    while (s[i] != '\0') 
    { 
     if (check[(int) s[i]]) 
      return false; 
     else 
     { 
     check[(int) s[i]] = true; 
     i++; 
     } 
    } 
    return true; 
}