读取带有浮点数的txt文件到二维矩阵中

Question

I'm trying to read "chol.txt" file with contents:

6 3 4 8
3 6 5 1
4 5 10 7
8 1 7 25

using the function: (where *ROW and *COL both have the value 4)

void ReadFile(float*** MATRIX, int* ROW, int* COL)
{
FILE* openF;

openF = fopen("chol.txt", "r");

for (int incROW = 0; incROW < *ROW; incROW++)
{
    for (int incCOL = 0; incCOL < *COL; incCOL++)
    {
        fscanf(openF, "%f", MATRIX[incROW][incCOL]);
        printf("MATRIX[%d][%d] has value %f\n", incROW, incCOL, (*MATRIX)[incROW][incCOL]);
    }
}

fclose(openF);
}

but it returns the text before crashing:

MATRIX[0][0] has value 6.000000
MATRIX[0][1] has value 0.000000
MATRIX[0][2] has value 4413697645709019316224.000000
MATRIX[0][3] has value 17751098170076127766626959360.000000

I can manually enter floats into the Matrix, but wanted to read from txt file now. Here is summary of my main():

void ReadFile(float*** MATRIX, int* ROW, int* COL);

int main()
{
int SIZE = 4;
float** M = NULL;

MakeNullMATRIX(&M, &SIZE, &SIZE);

ReadFile(&M, &SIZE, &SIZE);

return 0;
}

As requested MakeNullMATRIX:

void MakeNullMATRIX(float*** MATRIX, int* ROW, int* COL)
{
*MATRIX = (float **)malloc(*ROW * sizeof(float*));

for (int i = 0; i < *ROW; i++)
{
    (*MATRIX)[i] = (float *)malloc(*COL * sizeof(float));
}
}

Answer 1

Well, sorry, but this looks way too complicated than required...

Anyway, without offering too many changes; while it's required for you to pass the address of M to the MakeNullMATRIX , you don't have to do so for ReadFile . So...

1: Changing this line:

ReadFile(&M, &SIZE, &SIZE);

like this:

ReadFile(M, ... );  // removed &

2: Then this line:

void ReadFile(float*** MATRIX, int* ROW, int* COL);

into this:

void ReadFile(float ** MATRIX, ... );  // removed one *

3: And then these lines:

fscanf(openF, "%f", MATRIX[incROW][incCOL]);
...
printf("MATRIX[%d][%d] has value %f\n", incROW, incCOL, (*MATRIX)[incROW][incCOL]);

into these:

fscanf( ... , &( MATRIX[incROW][incCOL]) );  // enclosed it with &( )
...
printf( ... , MATRIX[incROW][incCOL] );  // removed (* )

Should make it work as you'd like it to work, as well as making your code somewhat more friendly to a random reader.

But I seriously cannot understand why not a simple one like this:

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <malloc.h>

void ReadFile( float * MATRIX, int * ROW, int * COL )
{
    FILE * openF = fopen( "chol.txt", "r" );

    if ( !openF ) {
        fprintf( stderr, "chol.txt is missing\n" );
        return;
    }

    for ( int incROW = 0; incROW < *ROW; incROW++ )
    {
        for ( int incCOL = 0; incCOL < *COL; incCOL++ )
        {
            fscanf( openF, "%f", MATRIX + (*ROW) * incROW + incCOL );
            printf( "MATRIX[%d][%d] has value %f\n", incROW, incCOL, *( MATRIX + (*ROW) * incROW + incCOL ) );
        }
    }

    fclose( openF );
}

int main( )
{
    int SIZE = 4;
    float * M = malloc( SIZE * SIZE * sizeof( *M ) );

    ReadFile( M, &SIZE, &SIZE );

    return 0;
}

Answer 2

调用fscanf()应该像

fscanf(openF, " %f", &((*MATRIX)[incROW][incCOL]));