The data collection code to the microSD card does not work

#include<BMI160Gen.h>
# include <CurieIMU.h>
# include <SDHCI.h>
SDClass SD;

#define FFT_LEN1024

void saveData(float*pDst, int dsize, intquantity){
  // contents of the savedata function
  // pDst is the pointer to the data, the next section is the size of the recorded data, and the next section is the number of data stores.
  static intgCounter = 0;// file name followed by
  char filename [16] = {};

  // Return without doing anything when more than the specified number of saves is reached
  if(gCounter>quantity){
    Serial.println("Data accumulated";
    return;
  }

    // open a data storage file
  sprintf(filename, "data%03d.csv", gCounter++);
  // delete a file if it already exists
  if(SD.exists(filename))SD.remove(filename);
  // Open File
  File myFile=SD.open(filename, FILE_WRITE);
  // Write Data
  for(inti=0;i<dsize;++i){
    myFile.println(String(pDst[i], 6));
  }
  myFile.close();//Close file
  Serial.println("Data saved as"+String(filename)));
}


void setup() {
  Serial.begin (230400);
  while(!Serial);

    // Wait for SD card to be inserted
  while(!SD.begin()){
    Serial.println("Insert SD card");
    };

  Serial.println("Initializing IMU device...");
  BMI 160.begin();

  BMI 160.setAccelerometerRange(2);
  BMI 160.setAccelerometerRate (1600);

  // Check acceleration measurement range and acceleration output rate before starting measurement  
  floata=BMI160.getAccelerometerRate();
  floatb=BMI160.getAccelerometerRange();
  Serial.println(a);
  Serial.println(b);
}

void loop() {
  float*ax;
  float*ay;
  float*az; // scaled accelerometer values
  BMI 160.readAccelerometerScaled(*ax,*ay,*az);

  // Show the acceleration as it is on the serial monitor
  // Serial.print("a:\t");
  // Serial.print(ax);
  // Serial.print("\t");
  // Serial.print(ay);
  // Serial.print("\t");
  // Serial.print(az);
  // Serial.println();  

  // Save a csv file with FFT_LEN/8 minutes of data on the microSD 10 times
  saveData(az, FFT_LEN/8,9); // Save z-axis output
}