关于 scanf 的入门问题

代码如下：

#include 
#include
int main(int)
{
    int a,b,c,d;
    printf("Please input four number,seperate by space");
    scanf("%3d%3d%3d%3d",&a,&b,&c,&d);
    printf("\na=%d,b=%d,c=%d,d=%d",a,b,c,d);
    system("pause");
}