#syntax wrong

15 messages · Page 1 of 1 (latest)

worldly fossil
# 
#include <string>

int main(){
    std::string alphabet {"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"};
    std::string key  {"XZNLWEBGJHQDYVTKFUOMPCIASRxznlwebgjhqdyvtkfuompciasr"};
    // in this version of the cypher, we'll use more string functions
    std::string secret_message{};
    size_t char_position{};


    std::cout << "Enter a secret message:\n";
    getline(std::cin, secret_message); // getline function gets the whole input including spaces
    

    for(size_t i = 0; i < secret_message.length(); ++i){
        char_position = alphabet.find(secret_message[i]);
        secret_message[i].swap(key[char_position]);
        



    }
Return 0;
} ```
terse gazelleBOT
#

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worldly fossil
#

The last line in the for loop shows an error on secret_message[i]

#

It says expression must have class type

#

But secret message is a stdstring how is it not class type

exotic copper
#
  • You're doing Return 0; instead of return 0;
  • Didn't include <algorithm> header to use the swap function

try this instead

std::swap(secret_message[i], key[char_position]);
worldly fossil
# 
#include <string>


int main(){

    std::string name = "Manuel";
    std::string name2 = "Bill";

    name2.swap(name);

    std::cout << name; // will output Bill



     return 0;
}```
#

I had a prior program that worked fine see

exotic copper
#

oh nvm the last thing I mentioned then

#

But it worked when I changed it to std::swap(secret_message[i], key[char_position]);
so I'm not sure what's going on

exotic copper
#

;compile ```c++
#include <iostream>
#include <string>

int main(){
char a = 'a';
char b = 'b';
int c = 1;
int d = 2;

a.swap(b);
c.swap(d);
std::cout << a; 
std::cout << c;

return 0;

}

rugged emberBOT
#
Compiler Output
<source>: In function 'int main()':
<source>:10:7: error: request for member 'swap' in 'a', which is of non-class type 'char'
   10 |     a.swap(b);
      |       ^~~~
<source>:11:7: error: request for member 'swap' in 'c', which is of non-class type 'int'
   11 |     c.swap(d);
      |       ^~~~
Build failed
nou2917 | c++ | x86-64 gcc 14.2 | godbolt.org
exotic copper
#

I guess the .swap() doesn't work with primitive types

edgy egret
exotic copper
#

Makes sense