Matrix c program help!!!

alright so i'm trying to make a matrix program that replaces, adds, multiplies and transposes matrices
as of right now i'm having trouble printing it out after i run a function

it goes something like this

input rows:
input columns:
then enter integer for each matrix position:

then it prints it out
(example)
1 2
3 4

then i run my replace function
input rows:
input columns:
then the integers for each matrix position
then it prints out
1 2
-435262 1
when it should be
4 3
2 1

please help!!
also i didn't know how to copy the code from the server, so if someone could tell me how to do that it would prob help you see what my code looks like thanks.

Since you are getting an apparently garbage value, my guess is you are using a variable uninitialized or accessing an array out of bounds.

Quote:

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i didn't know how to copy the code from the server

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I suppose it depends on a little details you forgot to mention: what server, what client, how do you connect to the server etc

i'm using this unix server for my college class, i kno its accessed through a ssh and then a user name then url
by the way i got the replace one to work, now it one to the addition, which is doing the same thing, shooting out crap values

If you are running Linux at home, you can use sshfs, otherwise sftp.

could u further explain

Google is your friend.

i dont think i can use those because they're all windows based, and im using a mac

alright heres my code

Code:

---

#include<stdio.h>


void showmatrix(int matrix[][], int row, int column)
{       
        int i, j ;
        int A[row][column];
        printf("Current Matrix is : \n");
        for(i=0; i<row; i++)
        {
                for(j =0; j<column; j++)
                { printf("%d\t", A[i][j]);
                } printf("\n");
        }
        printf("\n");
}

void setMatrix(int matrix[][], int row, int column)
{
        int i, j;
        int A[row][column];

       
        for(i=0; i<row; i++)
        {
                for(j =0; j<column; j++)
                {
                        printf("please input element (%d, %d) of the matrix:", i, j); scanf("%d", &A[i][j]);
                }
        }
}

void replaceA(int matrix[][4],int row,int column)
{
        int i, j;
        int A[row][column];

        printf("Please enter the number of rows for matrix:"); scanf("%d", &row);
            printf("Please enter the number of columns for matrix:"); scanf("%d", &column);

        for(i=0; i<row; i++)
        {
                for(j =0; j<column; j++)
                {
                        printf("please input element (%d, %d) of the matrix:", i, j); scanf("%d", &A[i][j]);
                }
        }
}               
int showmenu(int matrix[][], int row, int column)
{
        int choice = 0;
    printf("******MENU******\n");
/*        showmatrix(matrix, row, column);*/
       
        printf("(1)        Set matrix A\n");
        printf("(2)        Add a matrix B (matrix addition) \n");
        printf("(3)        Multiply with a matrix B (matrix multiplication) \n");
        printf("(4)        Transpose matrix A\n");
        printf("(5)        Exit \n");
        printf("Please give your choice: "); scanf("%d", &choice);

        return choice;
}

void replaceB(int matrixB[][],int row, int column)
{        int i, j;
        int B[row][column];
       
        for(i=0; i<row; i++)
        {
                for(j =0; j<column; j++)
                {       
                printf("please input element (%d, %d) of the matrix:", i, j); scanf("%d", &B[i][j]);
                }
        }
}

void add(int matrixA[][], int matrixB[][], int matrixC[][], int row, int column)
{        int i,j;
        int A[row][column];
        int B[row][column];
        int C[row][column];

        for(i=0; i<row; i++)
        {
                for(j =0; j<column; j++)
                { C[i][j] = A[i][j] +B[i][j];
                  A[i][j] = C[i][j];        }
               
        }
}
/*
void add(int matrixA[][], int matrixB[][], int row, int column)
{
        int i, j;
        int A[row][column];
        int B[row][column];
        int C[row][column];
        int value;
{
        for(i=0; i<row; i++)
        {
                for(j =0; j<column; j++)
                {
                        printf("please input element (%d, %d) of the matrix:", i, j); scanf("%d", &value);
                        B[i][j] = value;                       
                }
        }
}
        for(i=0; i<row; i++)
        {
                for(j =0; j<column; j++)
                { C[i][j] = A[i][j] + B[i][j];
                A[i][j] = C[i][j];                 
                }
        }       
}*/
/*
void multiply(int matrixA[][4], int rowA, int columnA, int matrixB[][4], int rowB, int columnB)
{
        int i,j, k;
        int A[i][j],B[i][k];
        int column, row, rowA, columnA, rowB, columnB, value, multi;
       
        rowA = row;
        columnA = column;
        rowB = columnA;
        printf("Please enter the number of columns for matrix A: ")
        scanf("%d", &columnB);
        for(i=0; i<rowB; i++)
        {               
                for(k=0; k<columnB; k++)
                {
                printf("please input element (%d, %d) of the matrix:", i, j); scanf("%d", &value);
                B[i][k] = value
                }       
        }
       
        for(i=0; i<rowA; i++)
        {
                for(j=0; j<columnB;j++)
                { multi = (A[i][j] * B[i][k]) + (A[i][j++] * B[i++][k];
                A[i][j] = multi;
       






}
void transpose(int matrix[][4], int row, int column)
{
}

*/

int main()
{
        int matrixA[4][4]; 
        int matrixB[4][4];
        int matrixC[4][4];
            int row=0, column =0;
        int rowB=0, columnB = 0;
        /* this variable is used to store the user's choice for the menu system */
        int choice = -1;

        printf("Please enter the number of rows for matrix:"); scanf("%d", &row);
            printf("Please enter the number of columns for matrix:"); scanf("%d", &column);
   
       
        setMatrix(matrixA, row, column);
        showmatrix(matrixA,row,column);       
       
        choice = showmenu(matrixA,row,column);

        while(1)
        {       
        if(choice == 1)
        { replaceA(matrixA,row,column) ;
        showmatrix(matrixA,row,column);       
        }
       
        if(choice == 2)
        {  replaceB(matrixB,row,column);
          add(matrixA, matrixB, matrixC,row, column);
        showmatrix(matrixA,row,column);  }       
        else if(choice ==5)
        { break;}

        choice = showmenu(matrixA,row,column);

        }

       



       
        return 0;
}

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i figured out the first problem
now it does the same thing when i run the addition program
i have yet to start on the multiplication and transpose

Quote:

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Originally Posted by kclew

i dont think i can use those because they're all windows based, and im using a mac

---

There should be very little, if anything, that is windows related in a matrix calculation program.

--
Mats

Quote:

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Originally Posted by matsp

There should be very little, if anything, that is windows related in a matrix calculation program.

--
Mats

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sorry bout that, but i figured out how to do it

Code:

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void showmatrix(int matrix[][], int row, int column)

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this could not be compiled - you can leave out only one dimention

no i was able to compile it and it worked for the first function

Quote:

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Originally Posted by kclew

no i was able to compile it and it worked for the first function

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Do you sometimes read the warning and error messages of the compiler?

so my biggest problem right now is that it wont output the right numbers,
i ran the add function and the output was
4 -45685678
2 -46893778

Quote:

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Originally Posted by vart

Do you sometimes read the warning and error messages of the compiler?

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ya and it didn't give me any, i could just run it

Quote:

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Originally Posted by kclew

ya and it didn't give me any, i could just run it

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But your problem is highly likely to be caused by the fact that the compiler doesn't know the dimensions of the array!

--
Mats

Quote:

---

Originally Posted by matsp

But your problem is highly likely to be caused by the fact that the compiler doesn't know the dimensions of the array!

--
Mats

---

but that is part of the my program, i'm supposed to input how many columns and rows into the function and from there it supposed to allow me to add and everything, which is not working

Quote:

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Originally Posted by kclew

but that is part of the my program, i'm supposed to input how many columns and rows into the function and from there it supposed to allow me to add and everything, which is not working

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Yes, but if you are passing a 2D array to another function, you need to, one way or another, supply the size of all but the final dimension to the compiler. If you don't, it will not be able to do the math of multiplying the row-number by column-size, which it needs to do to find the data in a particular row/column pair.

If you want it to be fully-flexible, then you need to find another way to pass your matrix pointer (e.g. pointer to pointer or do your own math to calculate the row/column position)

--
Mats

so how should i approach this, my max matrix is 4 so i put that in the 2nd bracket, but it still gives me these off numbers

Quote:

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Originally Posted by kclew

so how should i approach this, my max matrix is 4 so i put that in the 2nd bracket, but it still gives me these off numbers

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By second bracket, do you mean left or right? The one on the left is the one that needs to be sized.

--
Mats

i sized the one on the right, ill try switching it
nope still gives me two single digit numbers and then some junk