程序编写一程序，用随机生成的两个两位数及加号或减号，显示一数学算式（若是减法，要保证减法算式的被减数大于减数），提示学生输入计算结果，程序判断结果是否正确并给出提示

方法1使用 java . util . Random
Random (. nextint ( int bound ）生成一个从0（含）到 bound ( Random (). nextint ( int bound ）的随机整数。
例：
Random r = new Random );
int a = r . nextlnt (( max - min )+1)+ min ;
生成一个介于 min （含）和 max （含）之间的随机整数
方法2使用 Math . random )
Math . random （给出从0.0（含）到1.0例：
int a =( int )( Math . random ()*(( max - min )+1))+
min
生成一个介于 min （含）和 max （含）之间的随机整数

import java.util.Scanner;

/*

程序内容：随机生成两位整数的四则运算

完成时间：2017年3月23日

*/

public class calculator{

public static void main(String[] args){

int sum=0;

int sum1=0;

int p=0;

int n=0;

double d1;

double d2;

int x=10;

int i=0;

int answer;

boolean f=false;

String cx="";//重新生成错题

for(i=0;i

int a=(int)(Math.random()*100);

int b=(int)(Math.random()*100);

int c=(int)(Math.random()*4); //随机生成0到4任意一个数字

if(c==0)

{

d1=a+b;

cx = (a+"+"+b+"= ");

System.out.print(a+"+"+b+"= ");

Scanner in = new Scanner(System.in);

answer = in.nextInt();

if (d1==answer)

{

f=true;

System.out.println("========================");

System.out.println(" 恭喜你答对了 ");

System.out.println("========================");

//n++;

sum++;

}

else{

f=false;

System.out.println("========================");

System.out.println(" 很遗憾答错了 ");

System.out.println("========================");

sum1--;

System.out.println(cx);

answer = in.nextInt();

if (d1==answer)

{

f=true;

System.out.println("========================");

System.out.println(" 恭喜重新答对了 ");

System.out.println("========================");

sum++;

}

}

}

if(c==1)

{

d1=a-b;

cx = (a+"-"+b+"= ");

System.out.print(a+"-"+b+"= ");

Scanner in = new Scanner(System.in);

answer = in.nextInt();

if (d1==answer)

{

f=true;

System.out.println("========================");

System.out.println(" nice，正确 ");

System.out.println("========================");

sum++;

}

else{

f=false;

System.out.println("========================");

System.out.println(" 不好意思，下次努力 ");

System.out.println("========================");

sum1--;

System.out.println(cx);

answer = in.nextInt();

if (d1==answer)

{

f=true;

System.out.println("========================");

System.out.println(" nice，从新做正确 ");

System.out.println("========================");

sum++;

}

}

}

if(c==2)

{

d1=a*b;

cx = (a+"*"+b+"= ");

System.out.print(a+"*"+b+"= ");

Scanner in = new Scanner(System.in);

answer = in.nextInt();

if (d1==answer)

{

f=true;

System.out.println("========================");

System.out.println(" 你太优秀了，正确 ");

System.out.println("========================");

sum++;

}

else{

f=false;

System.out.println("==========================");

System.out.println("继续加油，下次一定可以做对");

System.out.println("==========================");

sum1--;

System.out.println(cx);

answer = in.nextInt();

if (d1==answer)

{

f=true;

System.out.println("======================== ");

System.out.println(" 正确,我说你可以吧 ");

System.out.println("======================== ");

sum++;

}

}

}

if(c==3)

{

d1=a/b;

cx = (a+"/"+b+"= ");

System.out.print(a+"/"+b+"= ");

Scanner in = new Scanner(System.in);

answer = in.nextInt();

if (d1==answer)

{

f=true;

System.out.println("========================");

System.out.println(" 很好，继续努力 ");

System.out.println("========================");

sum++;

}

else{

f=false;

System.out.println("========================");

System.out.println(" 没什么大不了，继续努力 ");

System.out.println("========================");

sum1--;

System.out.println(cx);

answer = in.nextInt();

if (d1==answer)

{

f=true;

System.out.println("==========================");

System.out.println(" 答案正确继续努力 ");

System.out.println("==========================");

sum++;

}

}

}

System.out.println("--------------------------");

System.out.println(" 正确题目得分为： ");

System.out.println(sum);

System.out.println("--------------------------");

System.out.println(" 错误题目得分为： ");

System.out.println(sum1);

System.out.println("--------------------------");

d2=sum+sum1;

System.out.println(" 最终得分为： ");

System.out.println(sum+"+"+sum1+"= "+d2);

System.out.println("--------------------------");

}

/*public int d2(int sum,int sum1){

int d2=sum-sum1;

return d2;*/

}

}

https://blog.csdn.net/weixin_39724266/article/details/110725626