C语言用fopen_s函数对wav文件计算时域信号的均值、均方值、方差，计算信号的自协方差矩阵

以下是C语言代码示例，其中使用了fopen_s函数打开wav文件，读取文件中的数据并计算时域信号的均值、均方值、方差以及自协方差矩阵。

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <math.h>

#define BUFFER_SIZE 1024

typedef struct {
    uint32_t ChunkID;
    uint32_t ChunkSize;
    uint32_t Format;
    uint32_t Subchunk1ID;
    uint32_t Subchunk1Size;
    uint16_t AudioFormat;
    uint16_t NumChannels;
    uint32_t SampleRate;
    uint32_t ByteRate;
    uint16_t BlockAlign;
    uint16_t BitsPerSample;
    uint32_t Subchunk2ID;
    uint32_t Subchunk2Size;
} WavHeader;

int main() {
    FILE* fp;
    WavHeader header;
    char* filename = "test.wav";
    float buffer[BUFFER_SIZE];
    size_t read_size;
    float mean = 0, rms = 0, variance = 0;
    float autocov[BUFFER_SIZE][BUFFER_SIZE] = {0};
    int i, j, k;

    // Open the WAV file
    if (fopen_s(&fp, filename, "rb") != 0) {
        printf("Failed to open file %s\n", filename);
        return 1;
    }

    // Read the WAV header
    fread(&header, sizeof(header), 1, fp);

    // Read the WAV data
    while ((read_size = fread(buffer, sizeof(float), BUFFER_SIZE, fp)) > 0) {
        // Calculate mean
        for (i = 0; i < read_size; i++) {
            mean += buffer[i];
        }

        // Calculate autocovariance
        for (i = 0; i < read_size; i++) {
            for (j = 0; j < read_size; j++) {
                for (k = 0; k < read_size - fmax(i, j); k++) {
                    autocov[i][j] += buffer[i + k] * buffer[j + k];
                }
            }
        }
    }

    // Close the WAV file
    fclose(fp);

    // Calculate mean
    mean /= header.Subchunk2Size / sizeof(float);

    // Calculate RMS
    for (i = 0; i < header.Subchunk2Size / sizeof(float); i++) {
        rms += pow(buffer[i] - mean, 2);
    }
    rms = sqrt(rms / (header.Subchunk2Size / sizeof(float)));

    // Calculate variance
    for (i = 0; i < header.Subchunk2Size / sizeof(float); i++) {
        variance += pow(buffer[i] - mean, 2);
    }
    variance /= (header.Subchunk2Size / sizeof(float));

    // Print results
    printf("Mean: %f\n", mean);
    printf("RMS: %f\n", rms);
    printf("Variance: %f\n", variance);

    // Print autocovariance matrix
    printf("Autocovariance matrix:\n");
    for (i = 0; i < BUFFER_SIZE; i++) {
        for (j = 0; j < BUFFER_SIZE; j++) {
            printf("%f ", autocov[i][j]);
        }
        printf("\n");
    }

    return 0;
}