剛學不久，將就用吧
win8.1下用gcc編譯通過，運行沒問題
#include?<stdio.h>void?getOption(int?*popt);
void?getNumbers(double?*pa,?double?*pb,?int?option);
double?calc(double?a,double?b,?int?option,?double?*presult);
void?printResult(double?a,?double?b,?int?option,?double?result);
int?main()
{
int?option?=?0;
double?a?=?0.0;
double?b?=?0.0;
double?result?=?0.0;
do
{
getOption?(&option);?//顯示菜單，讀選項
if?(option?!=?5)
{
getNumbers(&a,?&b,?option);//讀兩個操作數，若為除法，判別除數不為零若除數為零，要求用戶重新輸入
calc(a,?b?,option,?&result);//?完成運算，並返回結果
printResult(a,?b,?option,?result);//?輸出表達式及結果
}
}?while?(option!=5);
return?0;
}
void?getOption(int?*popt)//顯示菜單，讀選項
{
printf("1、加法?2、減法?3、乘法?4、除法?5、退出\n請輸入菜單項：");
while(scanf("%d",popt)!=1)fflush(stdin);//防止誤輸入程序崩潰
fflush(stdin);
while(*popt>5?||?*popt<1)
{
printf("請輸入1~5的數字，請重新輸入：");
while(scanf("%d",popt)!=1)fflush(stdin);
fflush(stdin);
}
}
void?getNumbers(double?*pa,?double?*pb,?int?option)//讀兩個操作數
{
printf("請輸入兩個操作數：");
scanf("%lf?%lf",pa,pb);
if(option?==?4)//若為除法，判別除數不為零若除數為零，要求用戶重新輸入
while(*pb?==?0)
{
printf("除數不能為0，請重新輸入除數：");
scanf("%lf",pb);
}
}
double?calc(double?a,?double?b,?int?option,?double?*presult)//?完成運算，並返回結果
{
switch(option)
{
case?1:
*presult?=?a?+?b;
break;
case?2:
*presult?=?a?-?b;
break;
case?3:
*presult?=?a?*?b;
break;
case?4:
*presult?=?a?/?b;
break;
default:
break;
}
return?*presult;
}
void?printResult(double?a,?double?b,?int?option,?double?result)//?輸出表達式及結果
{
switch(option)
{
case?1:
printf("%lf?+?%lf?=?%lf\n",a,b,result);
break;
case?2:
printf("%lf?-?%lf?=?%lf\n",a,b,result);
break;
case?3:
printf("%lf?×?%lf?=?%lf\n",a,b,result);
break;
case?4:
printf("%lf?÷?%lf?=?%lf\n",a,b,result);
break;
default:
break;
}
printf("\n");
}