错误C2228：'。words'的左边必须有class / struct / union

Question

当我尝试使用VS 2013编译此文件时出现以下错误。我已经链接了该文件，因为它似乎太大而无法复制和粘贴到此处。

Payload.cc(77) : error C2275: 'spectralFrameWord' : illegal use of this type as an expression
Payload.cc(22) : see declaration of 'spectralFrameWord'
Payload.cc(77) : error C2228: left of '.words' must have class/struct/union

码

#include <cstdio>
#include <cstdint>
using namespace std;

long getFileSize(FILE *file) {
    long currentPosition, endPosition;
    currentPosition = ftell(file);
    fseek(file, 0, 2);
    endPosition = ftell(file);
    fseek(file, currentPosition, 0);
    return endPosition;
}

struct frame {
    uint8_t bytes[535];
};

struct spectralFrame {
    uint8_t bytes[512];
};

struct spectralFrameWord {
    uint16_t words[256];
};

int main() {
    char *filePath = "C:\\Payload\\Untitled.bin";
    uint8_t *fileBuffer;
    FILE *file = NULL;
    file = fopen(filePath, "rb");
/*  if((file = fopen(filePath, "rb")) == NULL)
        cout << "Failure." << endl;
    else
        cout << "Success." << endl;
*/
    long fileSize = getFileSize(file);
    fileBuffer = new uint8_t[fileSize];
    fread(fileBuffer, fileSize, 1, file);
    fclose (file);
    long frameCount = fileSize / 535;
    frame *frames = new frame[frameCount];
    for(int i = 0, j = 0, k = 0; i < fileSize; i++) {
        frames[j].bytes[k++] = fileBuffer[i];
        if((i % 534) == 0) {
            j++;
            k = 0;
        }
    }
    delete fileBuffer;
    fileBuffer = NULL;
    spectralFrame *spectralFrames = new spectralFrame[frameCount];
    for(int i = 0; i < frameCount; i++) {
        for(int j = 22, k = 0; j < 534; j++) {
            spectralFrames[i].bytes[k++] = frames[i].bytes[j];
        }
    }
    delete frames;
    frames = NULL;
    spectralFrameWord *spectralFrameWords = new spectralFrameWord[frameCount];
    uint16_t word;
    for(int i = 0; i < frameCount; i++) {
        for(int j = 0, k = 0; i < 511;) {
            word = spectralFrames[i].bytes[j++] << 8;
            spectralFrameWords[i].words[k++] = word | spectralFrames[i].bytes[j++];
        }
    }
    delete spectralFrames;
    spectralFrames = NULL;
    filePath = "C:\\Payload\\Untitled.tsv";
    file = fopen(filePath, "w");
/*  if((file = fopen(filePath, "w")) == NULL)
        cout << "Failure." << endl;
    else
        cout << "Success." << endl;
*/
    for(int i = 0; i < 256; i++) {
        fprintf (file, "%u\t%u\n", i, spectralFrameWord[0].words[i]);
    }
    fclose (file);
    return 0;
}

Answer 1

你写了

spectralFrameWord[0].words

但意思是

spectralFrameWords[0].words

编译器无法使这一点变得更加清晰。 它说：

'.words'左边必须有class / struct / union

因此，它告诉您检查words左侧的哪个部分，以查看它不符合条件的原因。

---

使用new sometype[...]分配时，必须使用delete[]取消分配。 使用std::vector<T>可能更合适。

Answer 2

我觉得有一个错字。 至少在这里而不是

for(int i = 0; i < 256; i++) {
    fprintf (file, "%u\t%u\n", i, spectralFrameWord[0].words[i]);
}

应该

for(int i = 0; i < 256; i++) {
    fprintf (file, "%u\t%u\n", i, spectralFrameWords[0].words[i]);
}

使用仅在一个符号中不同的名称是一种非常糟糕的做法。