打算使用mcisendstring函数做一个简陋的播放器，但是输入指令之后，没有反应，也没有卡死，几秒种后自动结束进程，何解？

代码：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <windows.h>
#include <mmsystem.h>

int main(int argc, char *argv[])
{
    char cmd[1024];
    int i;
    int play,pause,stop,vd,vp,exit;
    begin:printf("---------MENU-----------\n");
    printf("pause             stop\n");
    printf("VolumeDown    VolumeUp\n");
    printf("play              exit\n");
    printf("If you want to do sth,you can enter the cmd(VolumeDown=vd,VolumeUp=vp)\n\n\n");
    scanf("%s",&cmd);
    if(strcmp(cmd,"play")==0)
    {
        mciSendString(L"open E:\\Nevada.mp3 alias music", NULL, 0, NULL);
        mciSendString(L"play music", NULL, 0, NULL);
        Sleep(5000);
    }
    else  if(strcmp(cmd,"pause")==0)
    {
        mciSendString(L"pause music", NULL, 0, NULL);
    }
    else  if(strcmp(cmd,"stop")==0)
    {
        mciSendString(L"close music", NULL, 0, NULL);
    }
    else  if(strcmp(cmd,"vd")==0)
    {
        printf("Still not support.");
    }
    else  if(strcmp(cmd,"vp")==0)
    {
        printf("Still not support.");
    }
    else if(strcmp(cmd,"resume")==0)
    {
        mciSendString(L"resume music", NULL, 0, NULL);
        getchar();
        getchar();
    }
    else  if(strcmp(cmd,"exit")==0)
    {
        for(i=0;i<100;i++)
        {
            printf("------------------------\n");
        }
        return 0;
    }
    else
    {
        for(i=0;i<100;i++)
        {
            printf("------------------------\n");
        }
        printf("Commander error!\n");
        goto begin;
    }
    return 0;
}