求解。。。。。（新手）

#include <stdio.h>
#include <stdlib.h>
int main()
{
    int a,b,c,d,e,f;
    scanf("%d",a);
    a=100*b+10*c+d;
    if (a>0 && 0<=b%2<=1 && 0<=c%2<=1 && 0<=d%2<=1);
        a=100*b+10*c+d;
        e=d*100+c*10+b;
        printf ("%d",e);
    if (a<0 && 0<=b%2<=1 && 0<=c%2<=1 && 0<=d%2<=1);
        a=100*b+10*c+d;
        f=0-d*100+c*10+b;
        printf ("%d",f);
    system("psuse");
    return 0;
}