CODEWITHSUNDEEP
carraysmatrixoutput
leovic
leovic

Reputation: 29

Matrix Output is garbage data

So, what I'm trying to do here is printout a matrix or simply just an array. Now, the input file has a set of integers. My problem is that when I output the matrix it's a bunch of random numbers. It's single digits too so I don't think it's an address like those associated with pointers. The first integer in the input file is suppose to be the array length or as I call it here "col".

 #define MAX 10
 int main()
 {
    int col,row; /* array dimensions */
    int i,j,k; /* counter variables */
    int n; /* temporary variable for elements*/
    int temp[MAX*MAX]; /* temporary array for row counting */
    int counter=0; /* counter variable for number of rows */
    int matrix[MAX][MAX]; /* input matrix */
    FILE *in; /* pointer for input file of elements */

/* INPUT */
printf("\nPlease enter your desired number of columns and the elements of your matrix.\n");
fscanf(in,"%d",&temp[0]); /* Enter matrix length */

col = temp[0]; /* assign integer value to col variable */

if( col < 1 || col > MAX){ /* Standard Error for invalid input */
    fprintf(stderr,"\nInvalid Length\n");
    exit(1);
}

/* PROCESSING */

while(fscanf(in,"%d",&n)!=EOF){ /* determine number of rows */
    temp[counter++]=n;
}

if(counter % col == 0){ /* standard error for exceeding/lesser amount of input*/
    fprintf(stderr,"\nInvalid amount of input\n");
    exit(1); /* quits out the program for error */
}
else{
    row = counter / col; /* determine number of rows */
}

for(i = 0; i < row; i++){ /* read the elements */
    for(j = 0; j < col; j++){
        for(k=1; k < counter; k++){
            matrix[i][j] = temp[k];
        }
    }
}

/* OUTPUT */

fprintf(stdout,"\nHere is your matrix:"); /* Matrix Header */

for(i=0; i < row; i++){ /* print out the input matrix */
    fprintf(stdout,"\n");
    for(j = 0; j < col; j++){
        fprintf(stdout,"%3d ",matrix[i][j]);
    }
}
fprintf(stdout,"\n");

The INPUT: 2 1 2 3 4 5 6

The OUTPUT: Please enter your desired number of columns and the elements of your matrix.

Here is your matrix:
  6   6
  6   6
  6   6

^ Now I don't know if our UNIX system is telling me something about myself or what. I'm scared now.

EDIT: Okay, I removed the comments between the lines of code. EDIT: I compiled and tested the program.

Upvotes: 0

Views: 87

Answers (2)

user3329166
user3329166

Reputation: 126

Problem is here, Every matrix i,j will get the same k.

   for(i = 0; i < row; i++){ /* read the elements */
        for(j = 0; j < col; j++){
            for(k=1; k < counter; k++){
                matrix[i][j] = temp[k];
            }
        }
    }

change it to,

int count=0; 
   for(i = 0; i < row; i++){ /* read the elements */
        for(j = 0; j < col; j++){
                count++;
                matrix[i][j] = temp[count];
        }
    }

Upvotes: 2

radomaj
radomaj

Reputation: 871

If that is the complete program, it seems like you never fopen()ed the file.

for(i = 0; i < row; i++){ /* read the elements */
    for(j = 0; j < col; j++){
        for(k=1; k < counter; k++){
            matrix[i][j] = temp[k];
        }
    }
}

There's your problem. How many dimensions does the matrix have? How many for loops are you using? Exactly.

Since for every iteration of the innermost loop i and j stay the same, while k goes from 1 to counter, you're rewriting matrix[i][j] over and over, until you always reach the same end value of k. Your code is equivalent to:

for(i = 0; i < row; i++){ /* read the elements */
    for(j = 0; j < col; j++){
        matrix[i][j] = temp[counter-1];
    }
}

Upvotes: 1

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