在c++17中，我们有filesystem库，它提供了轻松处理问题的工具。
示例：

#include <filesystem>
#include <iostream>
#include <string>

int main()
{
  std::string searchfilename;
  std::cout << "Please enter the filename to be searched\n";
  std::cin >> searchfilename;
  try {
    if (std::filesystem::remove(searchfilename))
       std::cout << "file " << searchfilename << " deleted.\n";
    else
       std::cout << "file " << searchfilename << " not found.\n";
  }
  catch(const std::filesystem::filesystem_error& err) {
     std::cout << "filesystem error: " << err.what() << '\n';
  }
}

您忘记关闭已打开的文件。因此，关闭文件，它应该可以工作。
注：该解决方案适用于@AkhileshSharma，并将评论作为答案，以回答问题。

当你尝试删除一个文件时，你应该立即处理remove函数的返回值。如果成功，它返回0，如果失败，它返回非零值。

const int result = remove( "no-file" );
if( result == 0 ){
    printf( "success\n" );
} else {
    printf( "%s\n", strerror( errno ) ); // No such file or directory
}

remove在stdio.h文件中
strerror在string.h中
因此，在执行remove函数之后，请检查它没有被删除的原因。
错误号存储在errno变量中，strerror可以将错误号Map到告诉失败原因的字符串。
你也可以使用perror命令测试错误代码和Linux终端

> perror 0
OS error code   0:  Success
> perror 1
OS error code   1:  Operation not permitted
> perror 2
OS error code   2:  No such file or directory
> perror 3
OS error code   3:  No such process
> perror 4
OS error code   4:  Interrupted system call
> perror 5
OS error code   5:  Input/output error

//you have to give the path of the file for example(path="C:\\data\\newfolder")
       System::IO::DirectoryInfo^  directory = gcnew System::IO::DirectoryInfo(path);
       for each(System::IO::FileInfo^ file in directory->GetFiles())
       {
       //for getting the extension of file(if you want to delete specific extension file)
       String^ s = file->Extension;
       if (file->Extension == ".png")
       {
        file->Delete();
       }
       }

下面是删除文件另一种简单方法

//complete location of file with path
std::string fileLocStr;
fileLocStr.append("C:\temp\test.txt");

//create dos command to delete file
std::string delFileCmd = "del /s /q " + fileLocStr;
cout << "delFileCmd: " << delFileCmd << endl;

//this executes the command
int delFileStatus = system(delFileCmd.c_str());