[RESOLVED] code generation

[2kaud]

what I mean is to call different 2d array with different size to the same function but not same time

Yes. post #11

template<size_t N, size_t M>
void random_letter(char (&array)[N][M])
{
	cout << N << endl << M << endl;
}

int main()
{
	char arr1[5][7];
	random_letter(arr1);

        char arr2[8][9];
        random_letter(arr2);

       return 0;
}

[david16]

this code went in infinite loop on the value 5

template < size_t N , size_t M >

void random_letter ( char ( &arrays ) [N][M] ) {

    srand ( time (0));
	
	char rnd = (rand() % 26) + 'A';
   
   cout << N << endl << M << endl;

}

and this is my case in main it should fill in with random numbers

   case 1 : {
	 
	char arr1 [5][5];

	random_letter ( arr1 );
			

}

[2kaud]

This works as expected and displays the size of the passed array.

#include <cstdlib>
#include <ctime>

template < size_t N, size_t M >
void random_letter(char (&arrays)[N][M]) {

	char rnd = (rand() % 26) + 'A';

	cout << N << endl << M << endl;

}

int main()
{
	srand((unsigned int)time(0));

	char arr1[5][5];

	random_letter(arr1);
}

Note that random_letter() doesn't actually do anything - apart from displaying the array sizes. It doesn't change any of the values in the array arrays.

If you have an infinite loop, what is happening in main() outside of the case? Have you debugged the program to find out the issue?

Also note that srand() is only required to be called once at the start of he program.

[david16]

actually my program should send the array according to user choice
let say I gave him 3 choices : 1- ....
2-.....
3-......

and usr chose 1 for example which is my first array of size [5][5] I have to send it to function to fill random letter and display it to user you see ? each case array get another size but I have in case 1 I showed you an infinite loop on value 5

[2kaud]

Do you mean something like this?

#include <cstdlib>
#include <ctime>
#include <iostream>
using namespace std;

template < size_t N, size_t M >
void random_letter(char (&arrays)[N][M]) {

	for (size_t n = 0; n < N; ++n)
		for (size_t m = 0; m < M; ++m)
			arrays[n][m] = (rand() % 26) + 'A';

}

template < size_t N, size_t M >
void display_array(char (&arrays)[N][M]) {

	cout << N << " x " << M << endl;

	for (size_t n = 0; n < N; ++n) {
		for (size_t m = 0; m < M; ++m)
			cout << arrays[n][m] << " ";

		cout << endl;
	}
}

int main()
{
	srand((unsigned int)time(0));
	
	int opt;

	do {
		cout << "Enter option (1, 2, 3 or 0 to quit): ";
		cin >> opt;

		switch (opt) {
			case 1:
				{
					char arr[5][5];

					random_letter(arr);
					display_array(arr);
				}
				break;

			case 2:
				{
					char arr[7][6];

					random_letter(arr);
					display_array(arr);
				}
				break;

			case 3:
				{
					char arr[3][6];

					random_letter(arr);
					display_array(arr);
				}
				break;

			case 0:
				break;

			default:
				cout << "Invalid input" << endl;
		}
	} while (opt != 0);
}

[david16]

exactly men you got the point . thx for that

[david16]

I have a question plz what's the difference between putting the break in the case or outside of the case ?? cause on output I'm getting same result .Thank you

[2kaud]

I have a question plz what's the difference between putting the break in the case or outside of the case ?? cause on output I'm getting same result .Thank you

break always goes with the case. You mean inside or outside of the {} ?
In terms of the code in post #20, none! Personally, I put a break (or a return if applicable) at the very end of the case statements (unless I want a follow-on). In this case it could go at the end of the statements in the {}.

[david16]

I see . now if the user was stupid and pressed something else that number while choosing from the menu lets say a letter or pressed enter without writing anything how do I avoid infinite loop ?? I use cin.ignore and cin.fail ?? If yes , can you tell me where is the best place to add them . You see what I mean ?? Thx

[2kaud]

I use cin.ignore and cin.fail

yes. But it's easier to use !cin than cin.fail.

can you tell me where is the best place to add them

yes. But try yourself first. That's how you learn! Hint. Consider another loop.

[david16]

ok I will try to do it my self then will come back

[david16]

Yes I got it . Since its a switch I can add it the default case like this

	default :

		cout << "\nInvalid input!\n" << endl;
              cin.clear();
              cin.ignore(1000, '\n');
  }

but still need one more thing and it will be complete . How to make it prompt invalid input or such message when user press enter without writing anything ?? I should use the !cin thing something like while ( !cin ) for example ?? thx

[2kaud]

How to make it prompt invalid input or such message when user press enter without writing anything

You can't using stream extraction if you want this. That's the way it works. >> will wait until a non-white space char is entered as extraction ignores all white-space before a character.

If you want to check for just <enter>, then you'll need something like using getline(), then check if the read string is empty or not. Then check if the entered value is valid or not.

PS I'm not convinced that your solution to non-digit input is always correct. Have you tried it with different combinations of good and bad (invalid number and non-numeric) input?

[david16]

yes it works

[2kaud]

[post moved to new thread http://forums.codeguru.com/showthrea...-c-dictionary] as relates to different topic]