UNIX API调用：使用read（）函数打开文件并将其打印到屏幕会添加额外的随机字符

Question

我正在尝试编写一个程序来使用UNIX API调用来比较两个文本文件。以下是我的两个文件的内容：

f1.txt

This is my sample.
It contains text
And for some reason
The last few chars
are duplicated?

f2.txt

This is another sample
Sometimes instead of
duplicating the last few chars,
it prints another new line
instead
4567865

我有一个打开并读取这些文件的cpp文件。我的OpenRead函数将文件名作为c字符串，并将文本文件的内容放入字符串并返回它。

    #include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <iostream>
#include <string>
#include <cstring>



using namespace std;

string OpenRead(const char*);

int main(int argc, char **argv)
{
    string text1 = "", text2 = "";

    string file1(argv[1]);
    string file2(argv[2]);


    text1 = OpenRead(file1.c_str());
    text2 = OpenRead(file2.c_str());
    cout << text1 << endl;
    cout << text2 << endl;

    exit(EXIT_SUCCESS);


 return 0;
}



string OpenRead(const char* filename)
{
    int inFD1;
    string text;

    char * buf = new char[fsize(filename)];

    inFD1 = open(filename, O_RDONLY, 0);
    if(inFD1 < 0) exit(EXIT_FAILURE);
    else
    {
         while (read(inFD1, buf, sizeof(int)) != 0) 
            text += buf; //cout << buf;

    }   

    close(inFD1);
    delete [] buf;
    return text;
}

size_t fsize(const char *filename) {
    struct stat st; 

    if (stat(filename, &st) == 0)
        return st.st_size;

    return -1; 
}

问题是，当我将其编译成可执行文件并运行我的命令：fileComp f1.txt f2.txt时，它会打开并读取它们几乎完全正常，但会产生奇怪的输出，其中额外的字符会附加到结尾。这是输出的样子：

This is my sample.
It contains text
And for some reason
The last few chars
are duplicated?
e
This is another sample
Sometimes instead of
duplicating the last few chars,
it prints another new line
instead
4567865
8

出于某种原因，它将e附加到第一个文件，将8附加到第二个文件。此行为因文本文件而异，但始终会将缓冲区中的随机字符附加到末尾。

Answer 1

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Answer 2

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Answer 3

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