C - extracting all Numbers from string

I got a String like by reading a file which got online one line. The C is a separator between the numbers.

3000C9.5452C5.644 ...

Now I want to extract all those numbers and write them into an double array whichs is called Matrix.

fgets(input_string, filesize, infile);
int matrix_size = (int) strtof(input_string, &input_end);
++input_string;
int binary_matrix_size = sizeof (double)*(matrix_size * matrix_size);
double *Matrix = malloc(binary_matrix_size);
for (int index = 0; index < (matrix_size * matrix_size); ++index) {
        while (!isdigit(input_string) && input_string) {
            ++input_string;
        }
        Matrix[index] = strtod(input_string, &input_end);
        input_string = input_end;
}

I tried to understand what you need.

#include<stdio.h>
#include <ctype.h>
#include <stdlib.h>

int main()
{
    char *input_string = "2C9.5452C5.644";
    char *input_end;

    int matrix_size = strtol(input_string, &input_end, 10);
    printf("Array size: %d\n", matrix_size);
    input_string = input_end;
    double *Matrix = malloc(sizeof(double)*(matrix_size));
    for (int index = 0; index < matrix_size; ++index) {
            while ( (*input_string != '\0') && !isdigit(*input_string) && input_string ) {
                ++input_string;
            }
            Matrix[index] = strtod(input_string, &input_end);
            printf("Retrieved value: %f\n", Matrix[index]);
            input_string = input_end;
    }

    free(Matrix);

    return 0;
}

Output is:

Array size: 2
Retrieved value: 9.545200
Retrieved value: 5.644000