vs2019C语言fopen_s通过文件名读WAV文件内的数据，计算数据中时域信号的均值、均方值、方差，计算信号的自协方差矩阵

以下是一个示例代码，可以通过文件名读取WAV文件并计算时域信号的均值、均方值、方差和自协方差矩阵：

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

#define BUFFER_SIZE 1024

typedef struct {
    char chunkId[4];
    int chunkSize;
    char format[4];
    char subchunk1Id[4];
    int subchunk1Size;
    short audioFormat;
    short numChannels;
    int sampleRate;
    int byteRate;
    short blockAlign;
    short bitsPerSample;
    char subchunk2Id[4];
    int subchunk2Size;
} WavHeader;

int main(int argc, char *argv[]) {
    if (argc != 2) {
        printf("Usage: %s <wav file>\n", argv[0]);
        return 1;
    }

    char *filename = argv[1];
    FILE *fp;
    errno_t err = fopen_s(&fp, filename, "rb");
    if (err != 0) {
        printf("Failed to open file %s\n", filename);
        return 1;
    }

    WavHeader header;
    int headerSize = sizeof(WavHeader);
    if (fread(&header, headerSize, 1, fp) != 1) {
        printf("Failed to read header from file %s\n", filename);
        return 1;
    }

    if (memcmp(header.chunkId, "RIFF", 4) != 0 ||
        memcmp(header.format, "WAVE", 4) != 0 ||
        memcmp(header.subchunk1Id, "fmt ", 4) != 0 ||
        memcmp(header.subchunk2Id, "data", 4) != 0 ||
        header.audioFormat != 1) {
        printf("Invalid WAV file format\n");
        return 1;
    }

    int numSamples = header.subchunk2Size / (header.bitsPerSample / 8);
    double *samples = (double *)malloc(numSamples * sizeof(double));
    if (samples == NULL) {
        printf("Failed to allocate memory\n");
        return 1;
    }

    int bytesPerSample = header.bitsPerSample / 8;
    char buffer[BUFFER_SIZE];
    int numBytesRead;
    int i, j;

    for (i = 0; i < numSamples; i++) {
        numBytesRead = fread(buffer, bytesPerSample, 1, fp);
        if (numBytesRead != 1) {
            printf("Failed to read sample from file %s\n", filename);
            free(samples);
            return 1;
        }

        double sample = 0.0;
        for (j = 0; j < bytesPerSample; j++) {
            sample += buffer[j] * pow(2, 8 * j);
        }
        sample /= pow(2, header.bitsPerSample - 1);
        samples[i] = sample;
    }

    fclose(fp);

    // calculate mean
    double mean = 0.0;
    for (i = 0; i < numSamples; i++) {
        mean += samples[i];
    }
    mean /= numSamples;
    printf("Mean: %f\n", mean);

    // calculate root mean square (RMS)
    double rms = 0.0;
    for (i = 0; i < numSamples; i++) {
        rms += pow(samples[i], 2);
    }
    rms /= numSamples;
    rms = sqrt(rms);
    printf("RMS: %f\n", rms);

    // calculate variance
    double variance = 0.0;
    for (i = 0; i < numSamples; i++) {
        variance += pow(samples[i] - mean, 2);
    }
    variance /= numSamples;
    printf("Variance: %f\n", variance);

    // calculate autocovariance matrix
    int lag;
    int numLags = 10;
    double *autocovariance = (double *)malloc(numLags * numLags * sizeof(double));
    if (autocovariance == NULL) {
        printf("Failed to allocate memory\n");
        free(samples);
        return 1;
    }
    memset(autocovariance, 0, numLags * numLags * sizeof(double));
    for (i = 0; i < numLags; i++) {
        for (j = 0; j < numLags; j++) {
            lag = j - i;
            if (lag >= 0 && lag < numSamples) {
                autocovariance[i * numLags + j] = (samples[lag] - mean) * (samples[lag + i] - mean);
            }
        }
    }
    printf("Autocovariance matrix:\n");
    for (i = 0; i < numLags; i++) {
        for (j = 0; j < numLags; j++) {
            printf("%f ", autocovariance[i * numLags + j]);
        }
        printf("\n");
    }

    free(samples);
    free(autocovariance);

    return 0;
}