阶层

#include <stdio.h>

#define END  -1     

longFactorial(intx);

main()

{               

    intx;

    while(1)          

    {               

        printf("input x:");

        scanf("%d", &x);     

        if(x <= END)

            break;             

        else

            printf("%d! = %ld\n", x, Factorial(x));

    }

}               

 

longFactorial(intx)

{               

    inti;

    longresult = 1;            

 

    for(i=1; i<=x; i++)

        result *= i;

    returnresult;                            

}