cant figure this out

[Ch1156]

Ok so i have a function that outputs 7 numbers in a row, now i want to output 5 lines of thosenumbers but i cannot figure out how to do it i have been trying to do it for about 10 minutes now.

string numbers = ("");
    vector<string> holdNumbers;
    bool getNumberLoopEnd = false;
    int loopCounter = 0;

    while(getNumberLoopEnd != true)
    {
        for(int i = 0; i < 7; i++)
        {
            numbers = '0' + rand() % 10;
            //cout << numbers;
        }
        holdNumbers.push_back(numbers);
        loopCounter++;
        if(loopCounter == 7)
        {
            break;
        }
    }

    for(int i = 0; i < 7; i++)
    {
        cout << holdNumbers[i];
    }

[Danny Toledo]

From what I gather, you just need to put it in a loop that iterates 5 times. Something like: http://ideone.com/08URzP

Maybe I gather wrong? Could you possibly provide us with a sample output?

[Ch1156]

well that code compiles but i just get a long line of characters, i want 5 lines of 7 characters in a row.

[Ch1156]

i tried something like this but it didnt work either

while(getNumberLoopEnd != true)
    {
        for(int i = 0; i < 7; i++)
        {
            numbers = '0' + rand() % 10;
            if(numbers.length() == 7)
            {
                holdNumbers.push_back(numbers);
            }
        }

        loopCounter++;
        if(loopCounter == 7)
        {
            break;
        }
    }
    for(int i = 0; i < 5; i++)
    {
        cout << holdNumbers[i];
    }

[JLBorges]

Write a nested loop.

#include <iostream>
#include <cstdlib>
#include <ctime>

int main()
{
    std::srand( std::time(nullptr) ) ;

    for( int i = 0 ; i < 5 ; ++i ) // 5 lines
    {
        for( int j = 0 ; j < 7 ; ++j ) // write 7 random digits per line
            std::cout << std::rand() % 10 << ' ' ;

        std::cout << '\n' ; // and end with a new line
    }
}

http://ideone.com/1mW9Wh

[Ch1156]

but i need to push back each line into a vector, so when i output the vector it will output 5 lines of 7 numbers. This only outputs 1 line

while(getNumberLoopEnd != true)
    {
        for(int i = 0; i < 5; i++)
        {
            for(int i = 0; i < 7; i++)
            {
                numbers = '0' + rand() % 10;
            }
            holdNumbers.push_back(numbers);
        }

        loopCounter++;
        if(loopCounter == 7)
        {
            break;
        }
    }

[JLBorges]

> but i need to push back each line into a vector,
> so when i output the vector it will output 5 lines of 7 numbers.

A std::string would be adequate.

#include <iostream>
#include <cstdlib>
#include <ctime>
#include <string>

int main()
{
    std::srand( std::time(nullptr) ) ;

    std::string five_x_seven ;

    for( int i = 0 ; i < 5 ; ++i ) // 5 lines
    {
        for( int j = 0 ; j < 7 ; ++j ) // write 7 random digits per line
        {
            five_x_seven += std::rand() % 10 + '0' ;
            five_x_seven += ' ' ;
        }
        five_x_seven += '\n' ; // and end with a new line
    }

    std::cout << five_x_seven ;
}

http://ideone.com/Tuo628

[Ch1156]

yeah but i need to use each line for something different so i need the vector.

[TheIdeasMan]

Hi Chay,

Can you figure out how to adapt JLBorges code to do what you want? You have 2 things : push_back a char to a string; push_back the string to a vector.

When doing your own code, try to get the simple things working first, then add complexity afterwards - preferably in small amounts. In this case get the code to build 1 string of 7 numbers working first, then add code to do 5 lines of them.

For loops are good when the number of iterations is known. While loops are better when some end condition is satisfied - like if you had some sentinel value to end the input for example.

I know this sounds boring & I might have said it before, but try to write pseudo-code with comments first, then translate to actual code:

// loop 7 times:
//       make a random number 1-9
//       push_back number to string
//end loop. 

Now add the extra complexity:

//loop 5 times:
//
//   loop 7 times:
//       make a random number 1-9
//       push_back number to string
//   end 7 times loop.
//
//push_back string into vector
//end 5 times loop  

So code the first part, then it become easy to do the second part.

Hope this helps a bit.


Edit: I didn't see JLBorges last post or Chay's replies. Just trying to get Chay to think about the process a bit. Any way probably better in JLB's expert hands.

[Danny Toledo]

well that code compiles but i just get a long line of characters

When I compile and run the code (I provided) above, I get:

1389010
1917054
4520981
1709523
7169976

Which, to me, sounds like what you are asking for:

output 5 lines of 7 numbers

Again, could you provide us with a sample output?

[Ch1156]

so this

numbers = rand() % 10 + '0';

is being pushed into a char or a string? if its a char i then have to convert it to a string correct? after that i can push it back into the vector which should then output on seperate lines?

[Ch1156]

"Again, could you provide us with a sample output?"

the output you provided is what i want, but it wont do that.

[Danny Toledo]

the output you provided is what i want, but it wont do that.

Huh? It works for me (it even worked on the link I provided). How did you use it in your code (did you copy + paste or write it out yourself)? It almost sounds like you are not printing to a newline for each iteration of the outer loop.

[TheIdeasMan]

@Chay

Why can't you use the code given to you? I am not purposely being harsh, but your own code is over complicated and full of contradictions. For example look at lines 15 and 16 - what is happening there?

You don't seem to understand the data structures you are using. It's simple - append a char to a string until the string has 7 chars, push_back that string to the vector. JLBorges code makes the string, so instead of appending the newline, just push that string into a vector, but make sure the string is reset to "" each time a new 7 digit string is started.

At the moment you a vector of 7 strings each of which has 1 char.

With your for loops, you have got away with using the index i for both of them, because i isn't used within the loops. This is bad practice and will cause you trouble one day.

This is why I mentioned the psuedo-code thing - it helps to think about the problem clearly, and can identify various things.

You are nearly there - just think clearly about what is going on.

[Ch1156]

Ok i got this pretty close to working i just am a little unsure of how to get it to break on a different line. keep in mind that each line has to be in a seperate vector element, so each vector element has to equal 1 line of 7 numbers, it cant be one long line of numbers that is new lined every 7 words.

void Player::hackingMethod()
{
    srand(time(0));

    char unconvertedNums;
    int convertedNums;
    vector<int> holdNumbers;
    stringstream convertToString;


        for(int i = 0; i < 5; i++)
        {
            for(int i = 0; i < 7; i++)
            {
                unconvertedNums = rand() % 10 + '0';
                unconvertedNums = ' ';
                convertToString << unconvertedNums;
                convertToString >> convertedNums;
            }
            holdNumbers.push_back(convertedNums);
            unconvertedNums = 0;
        }


    for(int i = 0; i < 7; i++)
    {
        cout << holdNumbers[i];
    }
    cout << "\n\n";
}

[TheIdeasMan]

keep in mind that each line has to be in a seperate vector element, so each vector element has to equal 1 line of 7 numbers, it cant be one long line of numbers that is new lined every 7 words.

Your code contradicts this, you now have a vector of ints.

Seriously, get rid of your function, and try modifying JLBorges code.

Remember, you have 2 data structures:

1. A string to append chars to.
2. A vector to push_back the already created string.

[Ch1156]

Ok so i did this

void Player::hackingMethod()
{
    srand(time(0));

    string five_x_seven;
    vector<string> numbers;

    for(int i = 0 ; i < 5 ; ++i) // 5 lines
    {
        for(int j = 0 ; j < 7 ; ++j) // write 7 random digits per line
        {
            five_x_seven += rand() % 10 + '0';
        }
        five_x_seven += '\n' ; // and end with a new line
        numbers.push_back(five_x_seven);
    }

    for(int i = 0; i < 3; i++)
    {
        cout << numbers[i];
    }
}

and when i output numbers it gives me 6 lines??? when i do it once it gives me just one but then i do 5 and it gives me 15 lines whats going on?

[Daleth]

Line 14 is really unnecessary. Also, TheIdeasMan already said to make sure the string is cleared each time.

numbers.push_back(five_x_seven);
five_x_seven = "";

Edit:
Hopefully to give you a hint of what is going on with your code:
1 = 1
3 + 2 + 1 = 6
5 + 4 + 3 + 2 + 1 = 15

[JLBorges]

void Player::hackingMethod()
{
    // srand(time(0));
    // seed the C lcg *once* at the beginning of the program
    // probably at the start of main()

    // string five_x_seven; // *** move this

    vector<string> numbers;

    for(int i = 0 ; i < 5 ; ++i) // 5 lines
    {
        string line ; // *** here
        // (start with a brand new *empty* string for each new line) 

        for(int j = 0 ; j < 7 ; ++j) // write 7 random digits per line
        {
            line += rand() % 10 + '0';
        }
        line += '\n' ; // and end with a new line
        numbers.push_back(line);
    }

    for( int i = 0; i < /* 3 */ numbers.size() ; i++)
    {
        cout << numbers[i];
    }
}