I want to use Inno Setup to install a third party exe file. How can I get inno setup to automatically run an exe file before running my installation files?

Prototype:
function Exec(const Filename, Params, WorkingDir: String; const ShowCmd: Integer; const Wait: TExecWait; var ResultCode: Integer): Boolean;
 
Description:
Executes the specified executable or batch file, using the same credentials as Setup/Uninstall. The Wait parameter specifies whether the function should return immediately or wait until the launched process has termimated or is idle. Returns True if the specified file was executed successfully, False otherwise. If True is returned and Wait is ewWaitUntilTerminated then ResultCode returns the exit code of the process. If False is returned then ResultCode specifies the error that occurred. Use SysErrorMessage(ResultCode) to get a description of the error.
 
Remarks:
TExecWait is defined as:
 
TExecWait = (ewNoWait, ewWaitUntilTerminated, ewWaitUntilIdle);
 
Use the ShellExec function instead if you need to launch a file that is not an executable or batch file.
 
Do not include quotes in the Filename parameter; the function will add them automatically.
 
The WorkingDir parameter can be an empty string, in which case it will try to extract a pathname from the Filename parameter and use that as the initial current directory for the process. If no pathname was specified in Filename, the process will inherit Setup/Uninstall's current directory.
 
If you have a single string containing both a filename and parameters (e.g. a command line obtained from an UninstallString registry value), you need not separate them yourself; just pass '>' in the Filename parameter, and the full command line in the Params parameter. (Note that when this is done, the function's special platform-independent support for .bat and .cmd files is disabled; it simply passes the specified command line to CreateProcess without any processing.)
 
By default, when Setup/Uninstall is running in 64-bit mode, this function disables WOW64 file system redirection when calling CreateProcess. It is possible to override this by calling EnableFsRedirection.
 
Example:
var
  ResultCode: Integer;
begin
  // Launch Notepad and wait for it to terminate
  if Exec(ExpandConstant('{win}\notepad.exe'), '', '', SW_SHOW,
     ewWaitUntilTerminated, ResultCode) then
  begin
    // handle success if necessary; ResultCode contains the exit code
  end
  else begin
    // handle failure if necessary; ResultCode contains the error code
  end;
end;See also:
ExecAsOriginalUser 
                                              

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[Code]
function InitializeSetup(): Boolean;
var
	ResultCode: Integer;
begin
 If Exec(ExpandConstant('{src}\FiletoExecute.exe'), '', '', SW_SHOW, ewWaitUntilTerminated, ResultCode) then
        result := true
    else
        result := false;
end;

                                              

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