如何获得窗口句柄？？？

#include <stdio.h>
#include <windows.h>

int main()
{
    HWND hwnd = FindWindowA("CalcFrame", "计算器");
    if (hwnd)
        printf("Handle:0x%08X\n",  hwnd);

    return 0;
}

//~ API:
//~ FindWindow
//~ FindWindowEx
//~ EnumWindow
//~ EnumChildProc
//~ .......