第二次作业

#include<stdio.h>
#include<math.h>
#include<windows.h>
int right=0;
int wrong=0;
void plus()
{
 int x,y,z;
 x=rand()%100;
 y=rand()%100;
 printf("请回答：\n\t\t %d + %d = ",x,y);
 scanf("%d",&z);
 if(x+y==z)
 {
  printf("回答正确!\n");
  right++;
 }
 else
 {
  printf("回答错误!\n");
  wrong++;
 }
}
void subtract()
{
 int x,y,z;
 x=rand()%100;
 y=rand()%100;
 printf("请回答：\n\t\t %d - %d = ",x,y);
 scanf("%d",&z);
 if(x-y==z)
 {
  printf("回答正确!\n");
  right++;
 }
 else
 {
  printf("回答错误!\n");
  wrong++;
 }
}
void multiply()
{
 int x,y,z;
 x=rand()%100;
 y=rand()%100;
 printf("请回答：\n\t\t %d * %d = ",x,y);
 scanf("%d",&z);
 if(x*y==z)
 {
  printf("回答正确!\n");
  right++;
 }
 else
 {
  printf("回答错误!\n");
  wrong++;
 }
}
void divide()
{
 int x,y,z;
 x=rand()%100;
 y=rand()%100;
 printf("请回答：\n\t\t %d / %d = ",x,y);
 scanf("%d",&z);
 if(x/y==z)
 {
  printf("回答正确!\n");
  right++;
 }
 else
 {
  printf("回答错误!\n" );
  wrong++;
 }
}
void main()
{
 int choise;
 int p=0;
 printf("\n\t\t\t欢迎进入小学四则运算\n\n");
 while(1)
 {
  printf("请选择：\n");
  printf("\t\t\t  加法运算（请输入1）\n");
  printf("\t\t\t  减法运算（请输入2）\n");
  printf("\t\t\t  乘法运算（请输入3）\n");
  printf("\t\t\t  除法运算（请输入4）\n");
  printf("\t\t\t  退出运算（请输入5）\n");
  if(p==0)
   scanf("%d",&choise);
  switch(choise)
  {
  case 1:
   plus();break; 
  case 2:
   subtract();break;   
  case 3:
   multiply(); break;  
  case 4:
   divide(); break;  
  case 5:
   return;
  }

  printf("\n\t\t\t继续该运算？（请输入1）\n");
  printf("\n\t\t\t重新选择？（请输入2）\n");
  printf("\n\t\t\t退出运算？（请输入3）\n");
  scanf("%d",&p);
  if(p==1)
   p=1;
  else if(p==2)
   p=0;
  else if(p==3)
   break;
  else
   printf("输入指令有误!请重新输入!\n");
 }
 printf("做对 %d 道\n做错 %d 道\n",right,wrong);
}