自动生成300道四则运算题

  1 public class questions {
  2
  3     public static void main(String[] args) {
  4         // TODO Auto-generated method stub
  5         int a=(int)(Math.random()*100);
  6         int b=(int)(Math.random()*100);
  7         int c=(int)(Math.random()*100);
  8        
  9         for(int i=0;i<300;i++){
 10             String q="";
 11             int ans=0;
 12             int[] flag=new int[2];
 13             for(int j=0;j<2;j++){
 14                 int f=(int)(Math.random()*4);
 15                 switch(f){
 16                 case 0:
 17                     if(j==0){
 18                         q=a+"+"+b;
 19                     }
 20                     else{
 21                         q=q+"+"+c;
 22                     }
 23                     flag[j]=0;
 24                     break;
 25                 case 1:
 26                     if(j==0){
 27                         q=a+"-"+b;
 28                     }
 29                     else{
 30                         q=q+"-"+c;
 31                     }
 32                     flag[j]=1;
 33                     break;
 34                 case 2:
 35                     if(j==0){
 36                         q=a+"*"+b;
 37                     }
 38                     else{
 39                         q=q+"*"+c;
 40                     }
 41                     flag[j]=2;
 42                     break;
 43                 case 3:
 44                     if(j==0){
 45                         q=a+"/"+b;
 46                     }
 47                     else{
 48                         q=q+"/"+c;
 49                     }
 50                     flag[j]=3;
 51                     break;
 52                 }
 53             }
 54             if(flag[0]<2){
 55                 if(flag[1]<2){
 56                     if(flag[0]==0){
 57                         ans=a+b;
 58                     }
 59                     else{
 60                         ans=a-b;
 61                     }
 62                     if(flag[1]==0){
 63                         ans+=c;
 64                     }
 65                     else{
 66                         ans-=c;
 67                     }
 68                 }
 69                 else{
 70                     if(flag[1]==2){
 71                         ans=b*c;
 72                     }
 73                     else{
 74                         if(c==0){
 75                             System.out.println("分母为零，此题无解");
 76                             continue;
 77                         }
 78                         ans=b/c;
 79                     }
 80                     if(flag[0]==0){
 81                         ans+=a;
 82                     }
 83                     else{
 84                         ans=a-ans;
 85                     }
 86                 }
 87             }
 88             else{
 89                 if(flag[0]==2){
 90                     ans=a*b;
 91                 }
 92                 else{
 93                     if(b==0){
 94                         System.out.println("分母为零，此题无解");
 95                         continue;
 96                     }
 97                     ans=a/b;
 98                 }
 99                 if(flag[1]==0){
100                     ans+=c;
101                 }
102                 else if(flag[1]==1){
103                     ans-=c;
104                 }
105                 else if(flag[1]==2){
106                     ans*=c;
107                 }
108                 else{
109                     if(c==0){
110                         System.out.println("分母为零，此题无解");
111                         continue;
112                     }
113                     ans/=c;
114                 }
115             }
116            
117             System.out.println(q);
118             System.out.println("答案是："+ans);
119         }
120     }
121
122 }