请修改下面的代码使得打印内容时可以同时输出行号：#includesystypesh#includesysstath#includefcntlh#includeunistdh#includeerrnoh#includestdioh#includestringh#define BUF_SIZE 30int mainint argc char argv char bufBUF_SIZE; int len

#include<sys/types.h> #include<sys/stat.h> #include<fcntl.h> #include<unistd.h> #include<errno.h>

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

#define BUF_SIZE 30

int main(int argc, char* argv[]) { char buf[BUF_SIZE]; int len = 0; int fd = -1; int line_num = 1; // 新添加的行号变量

if (argc != 2) {
	printf("wrong parameters\n");
	return -1;
}

fd = open(argv[1], O_RDONLY);

if (fd == -1) {
	printf("error in open file");
	printf("the error is: %s\n", strerror(errno));
	return -1;
}
else {
	//printf("open file success\n");
	while ((len = read(fd, buf, BUF_SIZE)) != 0) {
		for (int i = 0; i < len; i++) {
			if (buf[i] == '\n') {
				printf("%d: ", line_num++); // 输出行号
			}
			write(STDOUT_FILENO, &buf[i], 1);
		}
	}
}
if (fd > 0) {
	close(fd);
}
return 0;

}