Thread: multiplying a matrix inputed from a file

Actually, you should edit your post, highlight the code and press the # sign at the top of the edit window, to wrap your code in code tags.

Code should never be without it.

I pray your code is not indented as ugly as it appears, without the code tags.

The second code compiles without errors but there is a bus error. What should I do? And will this perform the correct operation?

I'm sorry, which variable has not already been initialized vart? And I tried taking the address of ma[i][j] but it still returns a bus error

k so I set multiply = to 1 and I added an address operator but its still giving me a bus error? thanks for your patience/

Code:

#include<stdio.h>
#define COL 6
#define ROW 4
int mult(int ma[][6]);

int main()
{
        int i =0;
        int j = 0;
        int multiply;
        FILE *infile;

        infile = fopen("t.rtf", "r");

        int ma[4][6];

        for (i = 0; i<4; i++)
                for (j = 0; j < 6; j++)
                        fscanf(infile, "%d*[,]\n", &ma[i][j]);/*no address*/
        printf("%d", mult(ma));
        fclose(infile);

        /*return 0;*/
}
int mult(int ma[4][6])
{
        int i = 0;
        int j = 0;
        int multiply = 1;
        for(i =0; i<ROW; i++)
                for(j = 0; j<COL; j++)
                        multiply *= ma[i][j];
        return multiply;
}

Hey guys so disregard everything I have done previosly I have made some serious headway on my program at the cost of my sleep and/or health. haha. So at this point the entire program should run except for I am having a problem with the easiest part. The part I am having trouble with has to go within my original matrix, ma, and determine both the MAX, and MIN values in a single function call. I know I am close but I keep getting a segmentation error. Thanks in advance.

Code:

#include<stdio.h>

int mult(int ma[][6], int m, int mb[][6], int row, int col);

int main()
{
        int i =0;
        int j = 0;
        int multiply;
        int ma[4][6];
        int mb[4][6];

        FILE *infile;
        FILE *outfile;

        infile = fopen("input_prelab3.txt", "r");
        outfile = fopen("output_prelab3.txt", "w");

        for (i = 0; i<4; i++)
                for (j = 0; j < 6; j++)
                        fscanf(infile, "%d", &ma[i][j]);/*no address*/

        printf("Enter a number to mutiply by:");
        scanf("%d", &multiply);
        mult(ma, multiply, mb, 4, 6);

        for (i = 0; i<4; i++)
        {
                for (j = 0; j < 6; j++)
                        fprintf(outfile, "%d ", mb[i][j]);
                fprintf(outfile, "\n", mb[i][j]);
        }

        printf("%d %d", max_min(ma));
        fclose(infile);
        fclose(outfile);
}

int mult(int ma[][6], int m, int mb[][6], int row, int col)
{
        int i = 0;
        int j = 0;
        for(i =0; i<row; i++)
                for(j = 0; j<col; j++)
                       mb[i][j] =  m * ma[i][j];
        return 0;
}

int max_min(int ma[][6], int row, int col)
{
        int i = 0;
        int j = 0;
        int MAX = ma[0][0];
        int MIN = ma[0][0];
        for(i =0; i < row; i++)
                for(j = 0; j < col; j++)
                {
                        if (ma[i][j]> MAX)
                                MAX == ma[i][j];
                        if (ma[i][j] < MIN)
                                MIN == ma[i][j];
                }
        return MAX, MIN;
}

You can return just one value from max_min(), not two.

Code:

max = max_min(ma, &min);

Where min is a variable in main() (which should be int main() BTW)

and the last lines in max_min is simply:

Code:

return max;
}

Does that make sense to you?

Well I thought it did so I changed my code to look like this but it doesnt output correctly. Did I change my code correctively. I believe my main function was already designated to a return an integer value before?

Code:

#include<stdio.h>

int mult(int ma[][6], int m, int mb[][6], int row, int col);

int main()
{
        int i =0;
        int j = 0;
        int min;
        int max;
        int multiply;
        int ma[4][6];
        int mb[4][6];

        FILE *infile;
        FILE *outfile;

        infile = fopen("input_prelab3.txt", "r");
        outfile = fopen("output_prelab3.txt", "w");

        for (i = 0; i<4; i++)
                for (j = 0; j < 6; j++)
                        fscanf(infile, "%d", &ma[i][j]);/*no address*/

        printf("Enter a number to mutiply by:");
        scanf("%d", &multiply);
        mult(ma, multiply, mb, 4, 6);

        for (i = 0; i<4; i++)
        {
                for (j = 0; j < 6; j++)
                        fprintf(outfile, "%d ", mb[i][j]);
                fprintf(outfile, "\n", mb[i][j]);
        }
        max = max_min(ma, &min);
        printf("%d %d", max_min(ma));
        fclose(infile);
        fclose(outfile);
}

int mult(int ma[][6], int m, int mb[][6], int row, int col)
{
        int i = 0;
        int j = 0;
        for(i =0; i<row; i++)
                for(j = 0; j<col; j++)
                       mb[i][j] =  m * ma[i][j];
        return 0;
}

int max_min(int ma[][6], int row, int col)
{
        int i = 0;
        int j = 0;
        int MAX = ma[0][0];
        int MIN = ma[0][0];
        for(i =0; i < row; i++)
                for(j = 0; j < col; j++)
                {
                        if (ma[i][j]> MAX)
                                MAX == ma[i][j];
                        if (ma[i][j] < MIN)
                                MIN == ma[i][j];
                }
        return MAX;
}

ugh I have been trying to figure this out for far too long. is there anyone who knows how I should fix this?

dbzx ur in my class aren't you? do you know how to do this?