C语言实现简单计算器

#include<stdio.h>
#include<windows.h>//Gotoxy
#include<coNIO.h>
#define width 80
#define height 30
void gotoxy(int x, int y);
void GreateFrame()
{
 int i = 0;
 for (i = 0 ; i <  width; i += 2)
 {
  gotoxy(i, 0); printf("■");
  gotoxy(i, height); printf("■");
 }
 for (i = 0; i < height + 1; i++)
 {
  gotoxy(0 , i); printf("■");
  gotoxy(width, i); printf("■");
 }
}
void Add()
{
 float i, j;
 printf("*加法运算*\n");
 scanf_s("%f %f", &i, &j);
 printf("%5.2f + %5.2f=%5.2f\n", i, j, i+j);
 _getch();
}
void Sub()
{
 float i, j;
 printf("*减法运算*\n");
 scanf_s("%f %f", &i, &j);
 printf("%5.2f - %5.2f=%5.2f\n", i, j, i -j);
 _getch();
}
void Mul()
{
 float i, j;
 printf("*乘法运算*\n");
 scanf_s("%f %f", &i, &j);
 printf("%5.2f * %5.2f=%5.2f\n", i, j, i * j);
 _getch();
}
void Div()
{
 float i, j;
 printf("*除法运算*\n");
 scanf_s("%f %f", &i, &j);
 printf("%5.2f / %5.2f=%5.2f\n", i, j, i / j);
 _getch();
}
int main(int arGC, char* argv[])
{
 int choose;
 while (1)
 {
  GreateFrame();
  gotoxy(width / 3, height / 3 + 2);
  printf("1.加法");
  gotoxy(width / 3, height / 3 + 4);
  printf("2.减法");
  gotoxy(width / 3, height / 3 + 6);
  printf("3.乘法");
  gotoxy(width / 3, height / 3 + 8);
  printf("4.除法");
  gotoxy(width / 3, height / 3 + 10);
  printf("5.退出程序");
  gotoxy(width / 3, height / 3);
  printf("请选择你要计算的方式:( )\b\b");
  scanf_s("%d", &choose);
  switch (choose)
  {
  case 1:system("cls");
    Add(); break;
  case 2:system("cls");
    Sub(); break;
  case 3:system("cls");
    Mul(); break;
  case 4:system("cls");
    Div(); break;
  case 5:
    exit(0);
  }
  system("cls");
 }
}
void gotoxy(int x, int y)
{
 COORD POS;
 POS.X = x;
 POS.Y = y;
 SetConsoleCursorPosition(GetStdHandle(STD_OUTPUT_HANDLE),POS);
}