原题链接:https://www.patest.cn/contests/pat-a-practise/1108
1108. Finding Average (20)
The basic task is simple: given N real numbers, you are supposed to calculate their average. But what makes it complicated is that some of the input numbers might not be legal. A "legal" input is a real number in [-1000, 1000] and is accurate up to no more than 2 decimal places. When you calculate the average, those illegal numbers must not be counted in.
Input Specification:
Each input file contains one test case. For each case, the first line gives a positive integer N (<=100). Then N numbers are given in the next line, separated by one space.
Output Specification:
For each illegal input number, print in a line "ERROR: X is not a legal number" where X is the input. Then finally print in a line the result: "The average of K numbers is Y" where K is the number of legal inputs and Y is their average, accurate to 2 decimal places. In case the average cannot be calculated, output "Undefined" instead of Y. In case K is only 1, output "The average of 1 number is Y" instead.
Sample Input 1: 7 5 -3.2 aaa 9999 2.3.4 7.123 2.35 Sample Output 1: ERROR: aaa is not a legal number ERROR: 9999 is not a legal number ERROR: 2.3.4 is not a legal number ERROR: 7.123 is not a legal number The average of 3 numbers is 1.38 Sample Input 2: 2 aaa -9999 Sample Output 2: ERROR: aaa is not a legal number ERROR: -9999 is not a legal number The average of 0 numbers is Undefined
给出一系列“数”,求出所有符合要求的数的个数和平均值。 要求是最多精确到小数后两位的数。
注意当个数为1和大于1的时候输出是不同的。
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 | #include "iostream" #include "string" #include "cmath" using namespace std; double s2d(string s){ int i,l = s.length(); int flag = 0; // 0: 正数 if(s[0] == '-') flag = 1; double num = 0; int dot = 0; for(i = flag; i < l; i++){ if(!((s[i] >= '0' && s[i] <= '9') || s[i] == '.')) return 9999; if(s[i] == '.'){ if(!dot) dot ++; else return 9999; }else{ if(dot) dot ++; num *= 10; num += s[i] - '0'; } } if(dot > 3) return 9999; if(flag) return (-1) * num/pow(10.0,dot?(dot -1):0); return num/pow(10.0,dot?(dot -1):0); } int main(){ string s ; int n,i,cnt = 0; double sum = 0,x; cin>>n; for(i = 0; i < n; i ++){ cin>>s; x = s2d(s); if(x >= -1000 && x <= 1000){ cnt ++; sum += x; }else cout<<"ERROR: "<<s<<" is not a legal number"<<endl; } if(cnt == 1) printf("The average of %d number is %.2f\n",cnt,sum/cnt); else if(cnt) printf("The average of %d numbers is %.2f\n",cnt,sum/cnt); else printf("The average of 0 numbers is Undefined\n"); system("pause"); } |
发表评论:
评论列表: