linux C编程之复制一半文件内容到另一个文件

#include <sys/stat.h>
#include <stdio.h>
#include <fcntl.h>
#include <stdlib.h>
int file_size(char* filename)
{
    struct stat statbuf;
    stat(filename,&statbuf);
    int size=statbuf.st_size;
    return size;
}
int main()
{
	//定义读取文件
    FILE *infile;
    char* inFileName = "/etc/passwd";
    infile = fopen(inFileName, "r");
    if (infile == NULL) {
        fprintf(stderr, "Cannot open file for reading: %s\n", inFileName);
        return 2;
    }
    //定义写入文件
    FILE *outfile;
    char* outFileName = "passwd_half";
    outfile = fopen(outFileName, "w");
    if (outfile == NULL) {
        fprintf(stderr, "Cannot open file for writing: %s\n", outFileName);
        fclose(outfile);
        return 3;
    }

    int inFileSize =  file_size(inFileName);
    printf("%d\n",inFileSize);
  
    char  buffer[256];
    int n = 1,sum = inFileSize / 2;
    fseek(infile, 0, SEEK_SET);
    while(sum > 0)
    {
        fread(buffer, n, 1, infile);
        sum = sum - n;
        fwrite(buffer, n, 1, outfile );
    }
	//记得关闭文件
    fclose(infile);
    fclose(outfile);
    //确认写入文件的大小
    int outFileSize =  file_size(outFileName);
    printf("%d\n",outFileSize);
    return 0;
}