求求各路大佬的解法，谢谢

供参考：

#include<stdio.h>

long getEvenNumbers(long num)
{
    long n=0,m=0,flg=0;
    while(num){
          n=num%10;
          if(n%2==0){flg=1; m=m*10+n;}
          num/=10;
    }
    n=0;
    while(m){
          n = n*10 + m%10;
          m /= 10;
    }
    if(flg == 0)return -1;
    else        return  n;
}

int main()
{
    long n;
    scanf("%ld",&n);
    printf("%ld\n",getEvenNumbers(n));
    
    return 0;
}