runtime cin error

hi guys, here i have a pretty noobish question...

say,

Code:

#include <iostream>
using namespace std;

class abc {

int value;
abc(char something) {
    switch(something) {
        case '1':
            cin >> value;
            break;
    }
};

main() {
abc(1);
return 0;
}

i have something like that, and theres no compiletime error, but when i run it, there is just some random error.

and i am just wondering if someone know any good free c++ debuggers. thanks.

What C++ compiler are you using? That code should not even compile.

well it is not really the actual thing. Anyway, im using digital mars.

Code:

#include <iostream>
#include <string>
#include <vector>
#include "tool.h"
using namespace std;


Key::Key(char choice) {
        cout << "Enter the key.";
	getinfo(choice);
}

void Key::getinfo(char choice) {
	switch(choice) {
		case '1':
		        cin >> value;cout << value;
		break;
	}
}

Cipher::Cipher() {
	cout << "Enter the encrypted-text.";
	cin >> Text;

	length = Text.length();
}


int main() {
	Menu();

	return 0;
}

void Menu(void) {
    
    char choice;                                 // What to do
        
// starting the menu              
    cout << "Menu:" << endl;
    cout << "   1. Sort the cipher text into shrift siphers according to the key length" << endl;
    cout << "   2. Frequency analysis the cipher-text." << endl;
    cout << "   3. Decrypt a monoalpheric cipher with a key." << endl;
    cout << "Enter q to quit.\n" << endl;

    cout << "Enter your choice: ";
    cin >> choice;

    switch(choice) {
        case '1' :
            SplitCode(choice);
            Menu();
            break;
        case '2' :
            Menu();
            break;
        case '3' :
            Menu();
            break;
        case 'q' :
            break;
        default :
            cout << "Please enter a valid choice." << endl;
            Menu();
            break;
    }

}

void SplitCode(char choice) {
    Cipher Vigenerec;                      // Create an instance of the cipher object

    Key Vigenerek(choice);                            // Create an instance of the key

    int Rmd = Vigenerek.value &#37; Vigenerec.length;// The number of odd digits out (uncompleted bits of key)
    int ArrayLen = (Vigenerec.length - Rmd) / Vigenerek.value;
    if(Rmd) ArrayLen++;

    vector<char> Split_Text[20];

    for(i=0;i<Vigenerek.value;++i) Split_Text[i].resize(ArrayLen);
    
    for(i=0;i<Vigenerec.length;++i) {
        int r = i % 5;                          // The bit of the key
        int r2 = (i-r)/5;                       // How many times did the key looped

        Split_Text[r][r2] = Vigenerec.Text[i];
    }

    for(i=0;i<Vigenerek.value;++i) {
        for(i1=0;i1<ArrayLen;i++) cout << Split_Text[i][i1];

        cout << "" << endl;
    }
}




#include <iostream>
#include <string>
#include <vector>
using namespace std;

// ///////////////variable declare
int i, i1;                                      // Loop variables

// ///////////////library functions declaration
char * strcat ( char*, char const* );

// ///////////////class or structures
class Key {
    
	public:

	int value;                                 // The actual key for shrift keys
	string code;                      // The key for other monoalpheric ciphers
	int length;                                 // The length of the key

	char Shrift_Key[2][26];              // The entire key for a shrift cipher

	Key(char choice);                         // Constructor
	void getinfo(char choice);
};

class Cipher {

    public:

    int length;                     // Length of array
    string Text;

    Cipher();                        // Constructor      
};

// /////////////////functions protype
void SplitCode(char choice);

void Menu(void);

it is actually that.

Let the guess: the second part is tool.h?

At a glance, there are a few potential problems:

1. You have a using directive (using namespace std) in your header that will spillover to files that include this header. Instead, fully qualify names used in headers.

2. Your header lacks header inclusion guards. This is not a problem here since you only include "tool.h" once, but could be a problem later.

3. Declare variables near their first use. Your global variables i and i1 clearly violate that guideline.

The problem you are currently facing may be from here:

Code:

for(i=0;i<Vigenerek.value;++i) {
    for(i1=0;i1<ArrayLen;i++) cout << Split_Text[i][i1];

    cout << "" << endl;
}

Notice that the outer loop uses i as the loop variable, the inner loop uses i1 as the loop variable, but the inner loop increment i instead of i1. Eventually, this would lead to an array out of bounds error for Split_Text.

thanks that really fixed the problem, but i still have a runtime error right after "cin >> value;" in void key::getinfo(). i put a cout there just to test it, but it wont exult either.

i still have a runtime error right after "cin >> value;" in void key::getinfo(). i put a cout there just to test it, but it wont exult either.

You could use a debugger to help you find out where exactly is the problem. If you somehow cannot use a debugger, then manually insert debug print statements in appropriate places, commenting out portions of code if necessary.

At the moment, the classes that model your problem domain are tightly coupled to the user interface. I think that you will find that your code would be easier to test if SplitCode() did not do all the work, but instead Key and Cipher had appropriate (member) functions that did some of the work. These functions would merely handle the manipulation of the problem domain, with other functions doing the work of getting input from the user.