高分求教！！！急！

#include <stdio.h>

#include <stdlib.h>

float Calculator(float d1, char op, float d2)

{

    float r = 0;

    switch (op)

    {

           case '+': r = d1+d2; printf("= %f\n",r); break;

           case '-': r = d1-d2; printf("= %f\n",r); break;

           case '*': r = d1*d2; printf("= %f\n",r); break;

           case '/': if (d2 != 0) {r = d1/d2; printf("= %f\n",r);}

                     else printf("除数不能为0\n");

                     break;

           default : printf("操作符有误\n");

    }

    return r;

}

void Headings()

{

     printf("************************************\n");

     printf("*           多功能计算器           *\n");

     printf("* [计算:按s] [退出:按x] [清屏:按c] *\n");

     printf("* [将上一结果作为第一运算数: 按a]  *\n");

     printf("************************************\n");

}            

int main(int argc, char *argv[])

{

    char Operator,Flag = 'Y';

    float Result = 0, Data_1, Data_2;

    while (1)

    {

          Headings();

          Flag = getch();

          fflush(stdin);

          if (Flag == 'x') break;

          else if(Flag == 'c') system("CLS");

          else if (Flag == 's')

          {

              printf("请输入数据(例如输入3+5将输出8):\n");

              scanf("%f%c%f",&Data_1,&Operator,&Data_2);

              Result = Calculator(Data_1,Operator,Data_2);

          }

          else if(Flag == 'a')

          {

               printf("上一结果为%f\n",Result);

               printf("请输入数据(例如输入+5将输出%f):\n",Result+5);

               scanf("%c%f",&Operator,&Data_2);

               Result =  Calculator(Result,Operator,Data_2);

          }

    }

    return 0;

}