Arduino C Multi dimensional array switching

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Im stuck with a piece of my Arduino code

Basically I have a multi dimensional array in which every index will store a random letter. But after a small time (eg. 900 milliseconds) every value in the index will move up to the index above it. Ofcourse when the index reaches e.g. [9][0] it will go to the largest index like [9][9]

E.g.: myArray[9][8] contains "K" and myArray[9][7] contains "L"

The "K" in myArray[9][8] will be put in myArray[9][7] and the "L" in myArray[9][7] will go to myArray[9][6] etc. etc

But I have no clue how to do this in C...
myArray[9][8] = myArray[9][7] obviously wouldnt work

asked Jan 3 at 10:57

Dylan Hamers

1

show us your code

– H.cohen
Jan 3 at 11:02

1

What's wrong with myArray[9][8] = myArray[9][7] ? Or better with temporary variable tmp = myArray[9][0]; myArray[9][0] = ...[1]; ...[1] = ...[2]; ... ...[9] = tmp

– Kamil Cuk
Jan 3 at 11:07

@KamilCuk I guess it moves it in the wrong direction. It would be myArray[9][7] = myArray[9][8] per the description. Generically a for loop with myArray[9][i] = myArray[9][i+1] could be used, with code to handle the wrap and a temp to store ``myArray[9][0]`.

– Fred
Jan 3 at 11:14

add a comment |

Im stuck with a piece of my Arduino code

E.g.: myArray[9][8] contains "K" and myArray[9][7] contains "L"

The "K" in myArray[9][8] will be put in myArray[9][7] and the "L" in myArray[9][7] will go to myArray[9][6] etc. etc

But I have no clue how to do this in C...
myArray[9][8] = myArray[9][7] obviously wouldnt work

asked Jan 3 at 10:57

Dylan Hamers

1

show us your code

– H.cohen
Jan 3 at 11:02

1

What's wrong with myArray[9][8] = myArray[9][7] ? Or better with temporary variable tmp = myArray[9][0]; myArray[9][0] = ...[1]; ...[1] = ...[2]; ... ...[9] = tmp

– Kamil Cuk
Jan 3 at 11:07

@KamilCuk I guess it moves it in the wrong direction. It would be myArray[9][7] = myArray[9][8] per the description. Generically a for loop with myArray[9][i] = myArray[9][i+1] could be used, with code to handle the wrap and a temp to store ``myArray[9][0]`.

– Fred
Jan 3 at 11:14

add a comment |

Im stuck with a piece of my Arduino code

E.g.: myArray[9][8] contains "K" and myArray[9][7] contains "L"

The "K" in myArray[9][8] will be put in myArray[9][7] and the "L" in myArray[9][7] will go to myArray[9][6] etc. etc

But I have no clue how to do this in C...
myArray[9][8] = myArray[9][7] obviously wouldnt work

asked Jan 3 at 10:57

Dylan Hamers

Im stuck with a piece of my Arduino code

E.g.: myArray[9][8] contains "K" and myArray[9][7] contains "L"

The "K" in myArray[9][8] will be put in myArray[9][7] and the "L" in myArray[9][7] will go to myArray[9][6] etc. etc

But I have no clue how to do this in C...
myArray[9][8] = myArray[9][7] obviously wouldnt work

c arrays multidimensional-array

asked Jan 3 at 10:57

Dylan Hamers

asked Jan 3 at 10:57

Dylan Hamers

asked Jan 3 at 10:57

Dylan Hamers

asked Jan 3 at 10:57

Dylan Hamers

asked Jan 3 at 10:57

Dylan Hamers

1

show us your code

– H.cohen
Jan 3 at 11:02

1

What's wrong with myArray[9][8] = myArray[9][7] ? Or better with temporary variable tmp = myArray[9][0]; myArray[9][0] = ...[1]; ...[1] = ...[2]; ... ...[9] = tmp

– Kamil Cuk
Jan 3 at 11:07

@KamilCuk I guess it moves it in the wrong direction. It would be myArray[9][7] = myArray[9][8] per the description. Generically a for loop with myArray[9][i] = myArray[9][i+1] could be used, with code to handle the wrap and a temp to store ``myArray[9][0]`.

– Fred
Jan 3 at 11:14

add a comment |

1

show us your code

– H.cohen
Jan 3 at 11:02

1

What's wrong with myArray[9][8] = myArray[9][7] ? Or better with temporary variable tmp = myArray[9][0]; myArray[9][0] = ...[1]; ...[1] = ...[2]; ... ...[9] = tmp

– Kamil Cuk
Jan 3 at 11:07

@KamilCuk I guess it moves it in the wrong direction. It would be myArray[9][7] = myArray[9][8] per the description. Generically a for loop with myArray[9][i] = myArray[9][i+1] could be used, with code to handle the wrap and a temp to store ``myArray[9][0]`.

– Fred
Jan 3 at 11:14

show us your code

– H.cohen
Jan 3 at 11:02

What's wrong with myArray[9][8] = myArray[9][7] ? Or better with temporary variable tmp = myArray[9][0]; myArray[9][0] = ...[1]; ...[1] = ...[2]; ... ...[9] = tmp

– Kamil Cuk
Jan 3 at 11:07

@KamilCuk I guess it moves it in the wrong direction. It would be myArray[9][7] = myArray[9][8] per the description. Generically a for loop with myArray[9][i] = myArray[9][i+1] could be used, with code to handle the wrap and a temp to store ``myArray[9][0]`.

– Fred
Jan 3 at 11:14

add a comment |

2 Answers
2

active

oldest

votes

There is not problem with assignment, but you must save the element you are writing over first.

In this example all the rewritten values are kept in the last slot of every row, this is just an example- not the only way to go, if you need to move the letters across the rows as well the idea is similar.

#include <stdio.h>

#include <stdlib.h>

#include <string.h>



void moveLettersInRow(char sArr[3], int row)

{

    int i = 0;

    int j = 0;

    char temp ;



    for (i = 0; i < row; ++i)

    {



       for(j = 2 ;j > 0;--j)

       {



           temp = sArr[i][j-1]; /*save the value to be rewritten */

           sArr[i][j-1]= sArr[i][2]; /* set the last val in its new place*/

           sArr[i][2]= temp; /* set the last elem to the latest rewritten value*/



       }

    }



}

void printArr(char arr[3], int size)

{

    int i = 0, j= 0;

    for(i = 0; i< size; ++i)

    {

        for(j = 0; j< 3; ++j)

        {

            printf("%c | ", arr[i][j]);

        }

        printf("n");

    }

}



int main()

{

   char arr[2][3]= {{'a','b','c'},{'a','b','c'}};

   moveLettersInRow(arr, 2);

   printArr(arr, 2);

   return 0;

}

answered Jan 3 at 12:08

H.cohen

47019

add a comment |

There are several ways to go about this. One would be to use a temporary variable while copying, as Kami Cuk and Fred pointed out.

Another way, which would avoid copying the values, would be to index the array using a modulo operation while reading the array.

myArray[9][(index + offset) % numberOfElementsInArray]

index and offset should both be positive integers.
numberOfElementsInArray is the number of elements in myArray[9]

To get a -1 offset with a positive integer, set offset to numberOfElementsInArray - 1

edited Jan 3 at 13:06

answered Jan 3 at 11:18

Pärt Johanson

871510

add a comment |

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2 Answers
2

active

oldest

votes

2 Answers
2

active

oldest

votes

There is not problem with assignment, but you must save the element you are writing over first.

#include <stdio.h>

#include <stdlib.h>

#include <string.h>



void moveLettersInRow(char sArr[3], int row)

{

    int i = 0;

    int j = 0;

    char temp ;



    for (i = 0; i < row; ++i)

    {



       for(j = 2 ;j > 0;--j)

       {



           temp = sArr[i][j-1]; /*save the value to be rewritten */

           sArr[i][j-1]= sArr[i][2]; /* set the last val in its new place*/

           sArr[i][2]= temp; /* set the last elem to the latest rewritten value*/



       }

    }



}

void printArr(char arr[3], int size)

{

    int i = 0, j= 0;

    for(i = 0; i< size; ++i)

    {

        for(j = 0; j< 3; ++j)

        {

            printf("%c | ", arr[i][j]);

        }

        printf("n");

    }

}



int main()

{

   char arr[2][3]= {{'a','b','c'},{'a','b','c'}};

   moveLettersInRow(arr, 2);

   printArr(arr, 2);

   return 0;

}

answered Jan 3 at 12:08

H.cohen

47019

add a comment |

There is not problem with assignment, but you must save the element you are writing over first.

#include <stdio.h>

#include <stdlib.h>

#include <string.h>



void moveLettersInRow(char sArr[3], int row)

{

    int i = 0;

    int j = 0;

    char temp ;



    for (i = 0; i < row; ++i)

    {



       for(j = 2 ;j > 0;--j)

       {



           temp = sArr[i][j-1]; /*save the value to be rewritten */

           sArr[i][j-1]= sArr[i][2]; /* set the last val in its new place*/

           sArr[i][2]= temp; /* set the last elem to the latest rewritten value*/



       }

    }



}

void printArr(char arr[3], int size)

{

    int i = 0, j= 0;

    for(i = 0; i< size; ++i)

    {

        for(j = 0; j< 3; ++j)

        {

            printf("%c | ", arr[i][j]);

        }

        printf("n");

    }

}



int main()

{

   char arr[2][3]= {{'a','b','c'},{'a','b','c'}};

   moveLettersInRow(arr, 2);

   printArr(arr, 2);

   return 0;

}

answered Jan 3 at 12:08

H.cohen

47019

add a comment |

There is not problem with assignment, but you must save the element you are writing over first.

#include <stdio.h>

#include <stdlib.h>

#include <string.h>



void moveLettersInRow(char sArr[3], int row)

{

    int i = 0;

    int j = 0;

    char temp ;



    for (i = 0; i < row; ++i)

    {



       for(j = 2 ;j > 0;--j)

       {



           temp = sArr[i][j-1]; /*save the value to be rewritten */

           sArr[i][j-1]= sArr[i][2]; /* set the last val in its new place*/

           sArr[i][2]= temp; /* set the last elem to the latest rewritten value*/



       }

    }



}

void printArr(char arr[3], int size)

{

    int i = 0, j= 0;

    for(i = 0; i< size; ++i)

    {

        for(j = 0; j< 3; ++j)

        {

            printf("%c | ", arr[i][j]);

        }

        printf("n");

    }

}



int main()

{

   char arr[2][3]= {{'a','b','c'},{'a','b','c'}};

   moveLettersInRow(arr, 2);

   printArr(arr, 2);

   return 0;

}

answered Jan 3 at 12:08

H.cohen

47019

There is not problem with assignment, but you must save the element you are writing over first.

#include <stdio.h>

#include <stdlib.h>

#include <string.h>



void moveLettersInRow(char sArr[3], int row)

{

    int i = 0;

    int j = 0;

    char temp ;



    for (i = 0; i < row; ++i)

    {



       for(j = 2 ;j > 0;--j)

       {



           temp = sArr[i][j-1]; /*save the value to be rewritten */

           sArr[i][j-1]= sArr[i][2]; /* set the last val in its new place*/

           sArr[i][2]= temp; /* set the last elem to the latest rewritten value*/



       }

    }



}

void printArr(char arr[3], int size)

{

    int i = 0, j= 0;

    for(i = 0; i< size; ++i)

    {

        for(j = 0; j< 3; ++j)

        {

            printf("%c | ", arr[i][j]);

        }

        printf("n");

    }

}



int main()

{

   char arr[2][3]= {{'a','b','c'},{'a','b','c'}};

   moveLettersInRow(arr, 2);

   printArr(arr, 2);

   return 0;

}

answered Jan 3 at 12:08

H.cohen

47019

answered Jan 3 at 12:08

H.cohen

47019

answered Jan 3 at 12:08

H.cohen

47019

answered Jan 3 at 12:08

H.cohen

47019

add a comment |

There are several ways to go about this. One would be to use a temporary variable while copying, as Kami Cuk and Fred pointed out.

Another way, which would avoid copying the values, would be to index the array using a modulo operation while reading the array.

myArray[9][(index + offset) % numberOfElementsInArray]

index and offset should both be positive integers.
numberOfElementsInArray is the number of elements in myArray[9]

To get a -1 offset with a positive integer, set offset to numberOfElementsInArray - 1

edited Jan 3 at 13:06

answered Jan 3 at 11:18

Pärt Johanson

871510

add a comment |

There are several ways to go about this. One would be to use a temporary variable while copying, as Kami Cuk and Fred pointed out.

Another way, which would avoid copying the values, would be to index the array using a modulo operation while reading the array.

myArray[9][(index + offset) % numberOfElementsInArray]

index and offset should both be positive integers.
numberOfElementsInArray is the number of elements in myArray[9]

To get a -1 offset with a positive integer, set offset to numberOfElementsInArray - 1

edited Jan 3 at 13:06

answered Jan 3 at 11:18

Pärt Johanson

871510

add a comment |

There are several ways to go about this. One would be to use a temporary variable while copying, as Kami Cuk and Fred pointed out.

Another way, which would avoid copying the values, would be to index the array using a modulo operation while reading the array.

myArray[9][(index + offset) % numberOfElementsInArray]

index and offset should both be positive integers.
numberOfElementsInArray is the number of elements in myArray[9]

To get a -1 offset with a positive integer, set offset to numberOfElementsInArray - 1

edited Jan 3 at 13:06

answered Jan 3 at 11:18

Pärt Johanson

871510

There are several ways to go about this. One would be to use a temporary variable while copying, as Kami Cuk and Fred pointed out.

Another way, which would avoid copying the values, would be to index the array using a modulo operation while reading the array.

myArray[9][(index + offset) % numberOfElementsInArray]

index and offset should both be positive integers.
numberOfElementsInArray is the number of elements in myArray[9]

To get a -1 offset with a positive integer, set offset to numberOfElementsInArray - 1

edited Jan 3 at 13:06

answered Jan 3 at 11:18

Pärt Johanson

871510

edited Jan 3 at 13:06

answered Jan 3 at 11:18

Pärt Johanson

871510

answered Jan 3 at 11:18

Pärt Johanson

871510

answered Jan 3 at 11:18

Pärt Johanson

871510

add a comment |

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