c++ - C++密码问题

Question

我对编码世界是陌生的，并且一直在尝试用c++制作一个密码，但是它抛出了一个错误，我不知道如何解决。帮助将不胜感激，这是代码

#include <iostream>                                               
#include <string>

using namespace std;


int main(){

/* Variables Declaration! */


string alphabets{"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"};   

string key{"XWZYLMNOPQRSTUVABCDEFGHIJKuvwxyzabcdefghijklmnopqrst"};

string input{};

string encrypted_message{};

string decrypted_message{};

/*----------------------------------------------------------------------------------------------*/

cout << "Welcome To the Cypher!" << endl;
cout << "-------------------------------------------------------------" << endl;



cout << "Enter the code: " << endl;
getline(cin,input);


/*Encryption Part Code*/ 

cout << "Encrypting!"<< endl;
cout << endl ;

for (char c:input) {

    size_t postition = alphabets.find(c);
    if (postition != string::npos){
        encrypted_message += key.at(postition);
    }
    else 
        encrypted_message += c;
}   
cout << endl ;
cout << encrypted_message << endl;


/* Decryption Part Code */

cout << "Decrypting!" << endl;
cout << endl ;

for (char c : encrypted_message) {

    size_t position = key.find(c);

    if (position != string::npos){
        decrypted_message += alphabets.at(c);
    } 

    else
        decrypted_message += c;

}   
/* --------------------------------------------------------------------------------------*/    



cout << endl;
cout << "-----------------------------------------------------------------------------" ;
cout << endl ;

return 0;
}

我收到的错误-

terminate called after throwing an instance of 'std::out_of_range'
what(): basic_string::at: __n (which is 88) >= this->size() (which is 52)

Answer 1

使用gdb打印进程转储的回溯，

    (gdb) bt
    #0  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50
    #1  0x00007ffff7aed535 in __GI_abort () at abort.c:79
    #2  0x00007ffff7eb5943 in ?? () from /lib/x86_64-linux-gnu/libstdc++.so.6
    #3  0x00007ffff7ebb8a6 in ?? () from /lib/x86_64-linux-gnu/libstdc++.so.6
    #4  0x00007ffff7ebb8e1 in std::terminate() () from /lib/x86_64-linux-gnu/libstdc++.so.6
    #5  0x00007ffff7ebbb14 in __cxa_throw () from /lib/x86_64-linux-gnu/libstdc++.so.6
    #6  0x00007ffff7eb7851 in ?? () from /lib/x86_64-linux-gnu/libstdc++.so.6
    #7  0x00007ffff7f4779f in std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::at(unsigned long) () from /lib/x86_64-linux-gnu/libstdc++.so.6
    #8  0x000055555555559b in main () at cypher.cc:61

根据＃8，第61行出现问题。

decrypted_message += alphabets.at(c);

根据＃7，尝试“at”功能时出现问题。

您的错误显示为

terminate called after throwing an instance of 'std::out_of_range' what(): basic_string::at: __n (which is 88) >= this->size() (which is 52)

这意味着您试图访问的n(88)超过了字母(52)的大小。

What you need to do is change "c" to "position".