普通计算器的实现

#include<stdio.h>
#include<conio.h>
#include<stdlib.h>
float get_answer()/*定义求结果的函数*/
{
    float a,b,answer;
    char flag;
    scanf("%f%c%f",&a,&flag,&b);
    switch(flag)
    {
    case '+': answer=a+b;break;
    case '-': answer=a-b;break;
    case '*': answer=a*b;break;
    case '/': answer=a/b;break;
    }
    return answer;
}
void main()/*主函数*/
{
    float b,answer;
    char flag;
    int point;
    system("title 普通计算器");
    system("color f0");
    printf("输入要保留的小数位:");
    scanf("%d",&point);
    printf("就绪！过程中按“Esc”退出！
");
    answer=get_answer();
    printf("=%.*f
",point,answer);
    while(1)
    {
        flag=getch();/*检测将要执行的命令*/
        if(flag==42||flag==43||flag==45||flag==47)/*判断是否是“+，-，*，/”*/
        {printf("%c",flag);/*输出运算符*/
        scanf("%f",&b);
        switch(flag)
        {
        case '+': answer+=b;break;
        case '-': answer-=b;break;
        case '*': answer*=b;break;
        case '/': answer/=b;break;
        }
        printf("%.*f",point,answer);}
        else if(flag==27)/*按Esc退出*/
            break;
        else/*再次执行运算*/
        {
            printf("
请输入“a+、-、*、/、b”：
");
            answer=get_answer();
            printf("=%.*f
",point,answer);
        }
    }
}