HDU 2004 （水）

Posted 2020-12-24 mimangdewo-a1

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=2004

题目大意： 给你成绩让你根据成绩打分
解题思路：

简单的if...else 应用

需要注意是，if....else if ....else ..if....不能写成 if...if.....if....else .....

比如 

 

 1         int q;
 2         int a = 12;
 3         if(a == 10)
 4             q = 1;
 5         if(a == 12)
 6             q = 2;
 7         if(a == 1)
 8             q = 3;
 9         else
10             q = 4;

最后会进入到

1         if(a == 1)
2             q = 3;
3         else
4             q = 4;

 

所以最后输出要么 q 是 3，要么 q 是 4，就算 q 已经赋值为 2 了，还会进入到这个地方，重新判断，赋值，因为 if 之间没影响，到了 if...else...才算完整的一个排斥选择。

代码：

 1     while(cin >> a)
 2     {
 3         if(a >= 90 && a <= 100)
 4             q = 0;
 5         else if(a >= 80 && a <= 89)
 6             q = 1;
 7         else if(a >= 70 && a <= 79)
 8             q = 2;
 9         else if(a >= 60 && a <= 69)
10             q = 3;
11         else if(a >= 0 && a <= 59)
12             q = 4;
13         else 
14             q = -1;
15         if(q == -1)
16             cout << "Score is error!" << endl;
17         else
18         {
19             char m = q + ‘A‘;
20             cout << m << endl;
21         } 
22     }

 或者

 1     while(cin >> score)
 2     {
 3         level = score / 10;
 4         if(score > 100 || score < 0)
 5             cout<<"Score is error!"<<endl;
 6         else
 7         {
 8             switch(level)
 9             {
10             case 10:
11             case 9:
12                 cout << "A" << endl;
13                 break;
14             case 8:
15                 cout << "B" << endl;
16                 break;
17             case 7:
18                 cout << "C" << endl;
19                 break;
20             case 6:
21                 cout << "D" << endl;
22                 break;
23             case 5:
24             case 4:
25             case 3:
26             case 2:
27             case 1:
28             case 0:
29                 cout << "E" << endl;
30                 break;
31             }
32         }
33     }