#include <stdio.h>
float get_number(void);
float charge_number(float t1);
int main(void)
{
float t=0.0,t1=0.0,anwser=0.0,tax=0.0;
char ch='0';
while(ch!='q')
{
printf("Enter the operation of your choice:\n");
printf("a.add\ts.subtract\n");
printf("m.multiply\td.divide\n");
printf("q.quit\n");
scanf("%c",&ch);
if(ch=='a'){
printf("Enter your first number: ");
t=get_number();
printf("Enter your second number: ");
t1=get_number();
t1=charge_number(t1);
anwser= t+t1;
printf("%f=%f+%f",anwser,t,t1);
break;}
else if(ch=='s'){
printf("Enter your first number: ");
t=get_number();
printf("Enter your second number: ");
t1=get_number();
t1=charge_number(t1);
anwser= t-t1;
printf("%f=%f-%f",anwser,t,t1);
break;}
else if(ch=='m'){
printf("Enter your first number: ");
t=get_number();
printf("Enter your second number: ");
t1=get_number();
t1=charge_number(t1);
anwser= t*t1;
printf("%f=%f*%f",anwser,t,t1);
break;}
else if(ch=='d'){
printf("Enter your first number: ");
t=get_number();
printf("Enter your second number: ");
t1=get_number();
t1=charge_number(t1);
anwser= t/t1;
printf("%f=%f/%f",anwser,t,t1);
break;}
else if(ch=='q')printf("bye!\n ");
else {getchar();
continue;}
}
return 0;
}
float get_number(void)
{
float t;
char erro;
while((scanf("%f",&t)!=1))
{
while((t=getchar())!='\n')//这里是关键 在循环中读取错误中的单个字符存到t中
{
putchar(t); //打印刚才存到的单个字符
}
printf(" is not a number.\nPlease enter an number,such as 2.5,-1.78E8,or 3:");
}
return t;
}
float charge_number(float t1)
{
while(t1==0.0)
{
printf("Enter a number other than 0: ");
t1=get_number();
}
return t1;
}
