distanceSensor.cpp

#include <stdlib.h>
#include <unistd.h>
#include <linux/i2c-dev.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <string.h>
#include <stdio.h>
#include <iostream>
#include </home/pi/Programming/C++/I2C/include/I2C.h>

using namespace std;

int main()
{
    int file;
    int address = 0x36;
    int time_us;
    double multiplier = 0.171500;

    unsigned char writeBuffer[4];
    unsigned char readBuffer[4];

    /*
     *
     *Attempt to open the file & start I2C communications.
     *"Also contains a check."
     *
     *
     */
    file = open("/dev/i2c-1", O_RDWR);
    if(file < 0)
    {
        std::cout << "[SYSTEM] Error to open file " << file << std::endl;
    }
    ioctl(file, I2C_SLAVE, address);
    cout << "[SYSTEM] Succesfully made a connection to the SLAVES" << endl;

    /*
     *
     *Build and send the command.
     *
     */

    int length = 1;
    writeBuffer[0] = UB_COMMAND_GET_FILTER_USM1;

    if(write(file, writeBuffer, length) != length)
    {
        cout << "[SYSTEM] Error sending command." << endl;
    }

    /*
     *
     *Read the reply.
     *
     */

    if(read(file, readBuffer, length) == length)
    {
        time_us = ((unsigned int) readBuffer[1] << 8) + (unsigned int) readBuffer[2];
        cout << "readBuffer[1] " <<(unsigned int) readBuffer[1] << endl;
        cout << ((unsigned int) readBuffer[1] << 8) << endl;
        cout << "readBuffer[2] " << (unsigned int) readBuffer[2] << endl;
        cout << "readBuffer[3] " << (unsigned int) readBuffer[3] << endl;
        cout << "readBuffer[4] " << (unsigned int) readBuffer[4] << endl;
        cout << "Value: " << time_us << endl;
    } else
    {
        cout << "[SYSTEM] Failed to read the reply." << endl;
    }

    double result = (double)time_us * multiplier;
    cout << "Distance (mm): " << result << endl;

    return 0;
}

Problem solved.
int length should not be 1 but 4 because the array need to hold 4 places.