写一段代码：根据文件名搜索文件

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

int main(int argc, char *argv[]) {
DIR *dir;
struct dirent *entry;
char *filename = argv[1];
int found = ;

if (argc != 2) {
printf("Usage: %s <filename>\n", argv[]);
exit(1);
}

dir = opendir(".");
if (dir == NULL) {
perror("opendir");
exit(1);
}

while ((entry = readdir(dir)) != NULL) {
if (strcmp(entry->d_name, filename) == ) {
printf("Found file: %s\n", filename);
found = 1;
break;
}
}

if (!found) {
printf("File not found: %s\n", filename);
}

closedir(dir);
return ;
}