Please help me with this problem

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create 5x5 massive with incidental elements from 0 to one(a[5][5] rand() % 100.Then change the places of elements which are located in the right and left of a diagonal of massive.I tried with several methods but none of them helped(

What I have tried:

#include<iostream>
#include<time.h>
using namespace std;

void main() {
	const int	S = 5;
	int arr[S][S] = {};
	for (int i = 0; i < S; i++) {
		for (int j = 0; j < S; j++) {
			arr[i][j] = rand() % 100;
			cout << arr[i][j] << "\t";

		}
		cout << "\n";

	}
	cout << "\n\n\n\n";
	for (int i = 0; i < S; i++) {
		for (int j = 0; j < S; j++) {
			arr[i][j] = rand() % 100;
			if (i < j)
				int m = 0;
			int m = j - i;
			arr[i][j] = arr[i + m][j - m]; { cout << arr[i + m][j - m] << "\t"; }
			if (j < i)
				int n = 0;
			int n = i - j;
			arr[i][j] = arr[i - n][j + n]; { cout << arr[i - n][j + n] << "\t"; }
			
			
		}
		cout << "\n";
	}
}

Posted 22-Dec-17 0:53am

Member 13589920

Updated 22-Dec-17 6:25am

jeron1

v2

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Member 13589920 22-Dec-17 6:54am

from 0 to 100*

Patrice T 22-Dec-17 7:33am

Use Improve question to update your question.

Richard MacCutchan 22-Dec-17 7:24am

Draw the array on a piece of paper and you can see the address co-ordinates of the cells in the diagonals.

2 solutions

Solution 2

Your changing process isnt correct, because you fill your matrix with new values.

I would make a copy and than use the transform mechanism to fill the target matrix.

C++

int source[S][S] = {};
memcpy( source, arr, 5*5*sizeof(int));//make a memory copy of the source data
//apply transformation algorithm
for (int i = 0; i < S; i++) {
    for (int j = 0; j < S; j++) {
      int k = i; // best guess
      int n = ... //TODO
      arr[i][j] = source[k][n];

Tip: fill your with simple test data (like ordered numbers) to debug and test the trasformation.

Posted 22-Dec-17 6:23am

KarstenK

Comments

Member 13589920 22-Dec-17 14:41pm

Can you write the whole code, please?

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Rick York · Accepted Answer · 2017-12-22T06:22:00

As Richard mentioned, drawing this out on paper will help you see the pattern. It it is very simple.

Also - have a look at the function swap in the standard library. It will take of that aspect of things for you.

Another thing - remember to seed the random number generator (RNG) with srand(). You have two options to seed it, at minimum. One is to use a predetermined value. Prime numbers are good for that like 47 or 43 and bigger values are OK too. With a predetermined seed you will get the same sequence of random values. The other option is to use a random value for the seed. Using time is common for this. Here is an example :

C++

int seed = time( NULL ) % RAND_MAX;

This will cause the RNG to return a more random sequence of values. It's up to you to choose what kind of sequence you want.

Lastly, you might to implement a function to display the matrix for you. You will need to do it twice so you might as well use one piece of code to do it. It might take a little while to figure out how to pass the matrix to a function so this is optional. It will likely be educational to figure it out though.

Here's a hint - you have the size defined as a constant and that's a good start. You can use typedef and define the matrix as a type and that will make it easier. ;)

Best of luck.