C++

Forum

 
classes

Pages: 12
Lbkulinski (34)
But your declaration would look like this:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
 
class Example
{
private:
     string ex;

public:
     Example()
     {
          //initialize private data member
          ex = "";
     } //end of default constructor

     void setParameter(string exString)
     {
          //assign value to private data member
          ex = exString;
     } //end of setParameter method

      type methodName(parameters)
     {
          //code goes in here
     } //end of method
};
Last edited on
axxotador (26)
ok so this is my code:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
 
#include <iostream>
#include <cstdlib>
#include <string>
#include <cctype>

using namespace std;

class Vigenere{

private:
	char shift(char c, int shamt);
	int shamt;
	string keyWord(string);

public:

// default constructor
Vigenere::Vigenere(int shiftAmount){ // Specify shift amount
	int shamt = shiftAmount;
}

Vigenere(string keyWord){
string key;
	for (int i = 0; i < key.size(); i++){
    if (key[i] >= 'A' && key[i] <= 'Z')
    	key += key[i];
    else if (key[i] >= 'a' && key[i] <= 'z')
    	key += key[i] + 'A' - 'a';
    }
}

Vigenere::encrypt(string text){ // Encrypts message

string message; 
	for (int i = 0, j = 0; i < text.length(); i++){
    char c = text[i];
    if (c >= 'a' && c <= 'z')
        c += 'A' - 'a';
    else if (c < 'A' || c > 'Z')
    message += (c + message[j] - 2 * 'A') % 26 + 'A';
        j = (j + 1) % message.length();
    }
    return message;
}

Vigenere::decrypt(string text){ // Decrypts message

string message;
    for (int i = 0, j = 0; i < text.length(); i++){
    char c = text[i];
    if (c >= 'a' && c <= 'z')
    	c += 'A' - 'a';
    else if (c < 'A' || c > 'Z')
    message += (c - message[j] + 26) % 26 + 'A';
    j = (j + 1) % message.length();
    }
    return message;
}

Vigenere::simplify(string text){ // Returns edited copy of string with only UPPERCASE letters
	string simplified = "";
	int size = text.size();
	for(int i = 0; i < size; i++){
    if (isalpha(text[i])){
    	simplified = simplified + (char) toupper(text[i]);
	}
}
	return simplified;
}

char Vigenere::shift(char c, int shamt){ // Shifts the order of the letters

	int result = (c-'A'+shamt);

	if (result >= 26) result = result - 26;
	if (result < 0) result = result + 26;
	
	return result+'A';
}

};

int main(int argc, char *argv[]){

  if (argc != 3){
    cerr << "USAGE: " << argv[0] << " -d|e shiftAmount" << endl;
    exit(1);
  }
  
  int shamt = atoi(argv[2]);
  
  bool encrypt;
  string option(argv[1]);
  string line;
  string encodedLine;	
  
  if (option == "-e"){
    encrypt = true;
  }	else {
    encrypt = false;
  }
  
  Vigenere cipher(shamt);
  
  while( getline(cin, line) ){
    if (encrypt){
      encodedLine = cipher.encrypt(cipher.simplify(line));
    } else {
      encodedLine = cipher.decrypt(line);
    }	
    cout << encodedLine << endl;
  }

	Vigenere cipher("VIGENERECIPHER");
    string encrypted = cipher.encrypt();
    string decrypted = cipher.decrypt(encrypted);
 
    cout << original << endl;

	return 0;
}
axxotador (26)
and this is where i get the messages:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
 
vigenere2.cpp:24:11: error: extra qualification on member 'Vigenere'
Vigenere::Vigenere(int shiftAmount){ // Specify shift amount
~~~~~~~~~~^
vigenere2.cpp:28:11: error: extra qualification on member 'keyWord'
Vigenere::keyWord(string key){
~~~~~~~~~~^
vigenere2.cpp:28:11: error: C++ requires a type specifier for all declarations
Vigenere::keyWord(string key){
          ^
vigenere2.cpp:38:11: error: extra qualification on member 'encrypt'
Vigenere::encrypt(string text){ // Encrypts message
~~~~~~~~~~^
vigenere2.cpp:38:11: error: C++ requires a type specifier for all declarations
Vigenere::encrypt(string text){ // Encrypts message
          ^
vigenere2.cpp:52:11: error: extra qualification on member 'decrypt'
Vigenere::decrypt(string text){ // Decrypts message
~~~~~~~~~~^
vigenere2.cpp:52:11: error: C++ requires a type specifier for all declarations
Vigenere::decrypt(string text){ // Decrypts message
          ^
vigenere2.cpp:66:11: error: extra qualification on member 'simplify'
Lbkulinski (34)
When you declare the methods inside of the class, you don't need the Vigenere::. So you would something like this:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
 
class Vigenere{

private:
	int shamt;
	string keyWord;

public:

// default constructor
Vigenere(int shiftAmount){ // Specify shift amount
	int shamt = shiftAmount;
}

Vigenere(string key){
     keyWord = key;
	for (int i = 0; i < keyWord.size(); i++){
    if (keyWord[i] >= 'A' && keyWord[i] <= 'Z')
    	keyWord += key[i];
    else if (keyWord[i] >= 'a' && keyWord[i] <= 'z')
    	keyWord += keyWord[i] + 'A' - 'a';
    }
}

string encrypt(string text){ // Encrypts message

string message; 
	for (int i = 0, j = 0; i < text.length(); i++){
    char c = text[i];
    if (c >= 'a' && c <= 'z')
        c += 'A' - 'a';
    else if (c < 'A' || c > 'Z')
    message += (c + message[j] - 2 * 'A') % 26 + 'A';
        j = (j + 1) % message.length();
    }
    return message;
}

string decrypt(string text){ // Decrypts message

string message;
    for (int i = 0, j = 0; i < text.length(); i++){
    char c = text[i];
    if (c >= 'a' && c <= 'z')
    	c += 'A' - 'a';
    else if (c < 'A' || c > 'Z')
    message += (c - message[j] + 26) % 26 + 'A';
    j = (j + 1) % message.length();
    }
    return message;
}

string simplify(string text){ // Returns edited copy of string with only UPPERCASE letters
	string simplified = "";
	int size = text.size();
	for(int i = 0; i < size; i++){
    if (isalpha(text[i])){
    	simplified = simplified + (char) toupper(text[i]);
	}
}
	return simplified;
}

char shift(char c, int shamt){ // Shifts the order of the letters

	int result = (c-'A'+shamt);

	if (result >= 26) result = result - 26;
	if (result < 0) result = result + 26;
	
	return result+'A';
}

};
axxotador (26)
ok that makes a LOT of sense now, thank you
Lbkulinski (34)
You're welcome. I just find it much easier to not have to keep using the scope resolution operator (::). Let me know if you have any other class questions. I try to make as many classes as I can. I find abstraction interesting.
axxotador (26)
ok that definitely works, once again thank you
axxotador (26)
ok if i run into another question i'll let you know, and i'm glad to know that you like abstraction, I myself i'm starting to love programming for its beautifull complexity
Lbkulinski (34)
Yes. Class hierarchies are fun once you get there. This site has some good tutorials on classes.
axxotador (26)
ok I have one last question
Lbkulinski (34)
Ok
axxotador (26)
when I comment out (// int shamt && // int shamt = shiftAmount) the program compiles without errors but when i type in my message it displays:

Floating point exception: 8

I don't know what this means
Lbkulinski (34)
try (/*int shamt && int shamt = shiftAmount*/)
axxotador (26)
ok i'll try that
axxotador (26)
i don't think that would work because it comments out more than I need to
axxotador (26)
ok so i solved the comment part, but I still get the "Floating point exception: 8" message when i run the program, I think the error is in my encrypt or decrypt functions and I cant seem to find it
axxotador (26)
ok so this are my encrypt and decrypt functions respectively:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
 
string encrypt(string text){ // Encrypts message

string message; 
	for (int i = 0, j = 0; i < int(text.length()); i++){
    	char c = text[i];
    if (c >= 'a' && c <= 'z')
        c += 'A' - 'a';
    else if (c < 'A' || c > 'Z')
    message += (c + message[j] - 26 * 'A') % 26 + 'A';
        j = (j + 1) % message.length();
    }
    return message;
}

string decrypt(string text){ // Decrypts message

string message;
    char c;
    for (int i = 0, j = 0; i < text.length(); i++){
    	c = text[i];
    if (c >= 'a' && c <= 'z')
    	c += 'A' - 'a';
    else if (c < 'A' || c > 'Z')
    message += (c - message[j] + 26) % 26 + 'A';
    j = (j + 1) % message.length();
    }
    return message;
}

Lbkulinski (34)
Ok, so it doesn't compile at all?
Topic archived. No new replies allowed.
Pages: 12