c - 输出与输入 c 不同

Question

所以我一直在尝试用 c 奇偶校验位做一些事情。但由于某种原因，输出与输入不同。输入为：0000000 0061 0000001 输出为：0000000 7f7f 0000002

由于某种原因，输出比输入高一个，我不知道为什么会发生这种情况，因为我使用相同的代码来获取高奇偶校验 + d0, d1, d2, d3

有人可以告诉我我的代码有什么问题以及如何解决这个问题吗？

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

int main(int argc, char *argv[])
{
    FILE *inputFile, *outputFile;


    char buffer[100];

    int res;

    int charFile;

    int byte;
    int d0, d1, d2, d3;
    int p0, p1, p2;

    int highNibble; //for getting the high nibble
    int lowNibble;  //for getting the low nibble

    if (argc == 3)
    {
        printf("The first argument is %s\n", argv[0]);
        printf("The first argument is %s\n", argv[1]);
        printf("The first argument is %s\n", argv[2]);
        inputFile = fopen(argv[1], "r");  //opening the .txt file and reading it
        outputFile = fopen(argv[2], "w"); //opening the .txt file and writing to it

        if (inputFile == NULL)
        {
            printf("There has been a problem while opening the file %s\n", argv[1]); //show this when a error occus while opening the .txt
        }
        else if (outputFile == NULL)
        {
            printf("There has been a problem while writing to the file %s\n", argv[2]); //show this when a error occus while opening the .txt
        }
        else
        {
            res = fread(buffer, sizeof(char), 1, inputFile);

            while (res != 0) //Found this function on the internet
            {
                printf("a\n");
                charFile = fgetc(inputFile); //Used to obtain the input form a file as a single character at a time.
                byte = (int)charFile;
                //get high nibble
                highNibble = (byte >> 4) & 0x0f;
                //get low nibble
                lowNibble = (byte & 0x0f);
                //d0, d1, d2, d3 + high nibble
                d0 = (highNibble >> 0) & 0b0001;
                d1 = (highNibble >> 1) & 0b0001;
                d2 = (highNibble >> 2) & 0b0001;
                d3 = (highNibble >> 3) & 0b0001;
                //p0, p1, p2
                p0 = (d0 + d1 + d2) % 2;
                p1 = (d0 + d1 + d3) % 2;
                p2 = (d1 + d2 + d3) % 2;

                uint8_t finalByteParityHigh = 0;

                // Add p0
                finalByteParityHigh = p0 << 0;
                // Add p1
                finalByteParityHigh |= p1 << 1;
                // Add p2
                finalByteParityHigh |= p2 << 2;
                // Add d0
                finalByteParityHigh |= d0 << 3;
                // Add d1
                finalByteParityHigh |= d1 << 4;
                // Add d2
                finalByteParityHigh |= d2 << 5;
                // Add d3
                finalByteParityHigh |= d3 << 6;
                fputc(finalByteParityHigh, outputFile); //High comes first in the table

                //do, d1, d2, d3 + low nibble
                d0 = (lowNibble >> 0) & 0b0001;
                d1 = (lowNibble >> 1) & 0b0001;
                d2 = (lowNibble >> 2) & 0b0001;
                d3 = (lowNibble >> 3) & 0b0001;
                //p0, p1, p2
                p0 = (d0 + d1 + d2) % 2;
                p1 = (d0 + d1 + d3) % 2;
                p2 = (d1 + d2 + d3) % 2;

                uint8_t finalByteParityLow = 0;

                // Add p0
                finalByteParityLow = p0 << 0;
                // Add p1
                finalByteParityLow |= p1 << 1;
                // Add p2
                finalByteParityLow |= p2 << 2;
                // Add d0
                finalByteParityLow |= d0 << 3;
                // Add d1
                finalByteParityLow |= d1 << 4;
                // Add d2
                finalByteParityLow |= d2 << 5;
                // Add d3
                finalByteParityLow |= d3 << 6;
                fputc(finalByteParityLow, outputFile);  //Low comes second in the table
            }
        }
        fclose(inputFile);  //close the input file
        fclose(outputFile); //close the output ifle
    }
    else
    {
        printf("you need to give 3 arguments");
    }
}

标签： cbitparity