packageSizeyunsuan;/*** 30道100以内四则运算

*

**/

public classRandom {public static int getRandom( int n, intm)

{//产生n->m的随机数

return (int) (Math.random() * (m - n) +n);

}public static chargetCharRandom()

{//随机产生四种运算符

char sign = 0;intSn;

Sn= getRandom(1,5);switch(Sn)

{case 1:sign = '+' ;break;case 2:sign = '-' ;break;case 3:sign = '×' ;break;case 4:sign = '÷' ;break;

}returnsign;

}public static voidmain(String[] args) {//TODO Auto-generated method stub

int i = 0;do{int x = (int) (Math.random() * (100 - 1 )+ 1); //产生1-100的随机数

int y = (int) (Math.random() * (100 - 1 )+ 1); //产生1-100的随机数

char sign =getCharRandom();/** 判断乘法的范围*/

switch(sign)

{case '+':

System.out.println("("+ (i+1) +")"+ x + " " + sign + " " + y + "=");

i++;break;case '-':if(x < y) //判断减数与被减数的大小关系

{inttemp;

temp=x;

x=y;

y=temp;

}

System.out.println("("+ (i+1) +")"+ x + " " + sign + " " + y + "=");

i++;break;case '×':

{

x= (int) (Math.random() * (10 - 1 )+ 1);//新生成x,y<9的随机数

y = (int) (Math.random() * (10 - 1 )+ 1);

System.out.println("("+ (i+1) +")"+ x + " " + sign + " " + y + "=");

i++;

};break;case '÷':do //循环生成除法

{

y= (int) (Math.random() * (10 - 1 )+ 1);

x= (int) (Math.random() * (9*y - 1 )+ 1);

}while(x % y != 0) ;

System.out.println("("+ (i+1) +")"+ x + " " + sign + " " + y + "=");

i++;break;

}/*if(sign == '×')

{

x = (int) (Math.random() * (10 - 1 )+ 1);//新生成x,y<9的随机数

y = (int) (Math.random() * (10 - 1 )+ 1);

System.out.println( "("+ (i+1) +")"+ x + " " + sign + " " + y + "=" );

i++;

}*/

/** 加减法判断*/

/*if(sign == '+' || sign == '-')

{

if(x < y) //判断减数与被减数的大小关系

{

int temp;

temp = x;

x = y;

y = temp;

}

System.out.println( "("+ (i+1) +")"+ x + " " + sign + " " + y + "=" );

i++;

}*/

/** 除法判断*/

/*if(sign == '÷')

{

do //循环生成除法

{

y = (int) (Math.random() * (10 - 1 )+ 1);

x = (int) (Math.random() * (9*y - 1 )+ 1);

}

while(x % y != 0) ;

System.out.println( "("+ (i+1) +")"+ x + " " + sign + " " + y + "=" );

i++;

}*/}while(i<30);

}

}