How to call another application in C++

Simple Code which calls another exe file named trojan.exe

#include 
#include 
using namespace std;

void file()
{
   ShellExecute(NULL, "open", "C:\\Program Files\\trojan\\trojan.exe",
                                NULL, NULL, SW_SHOWNORMAL);
}

int main()
{
file();
return 0;
}

NOTE: 

To use non-8.3 filenames on the command line, either escape the space ('Program\ Files' or "Program\\ Files\" in a C string), enclose the
path in quotes ('"C:/Program Files/"') or use the 8.3 abbreviation ('Progra~1').

Using something like %SystemDrive%\program files\sub directory\program.exe if C: isn't the default directory as shown in the
above code.