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
1 #include<cstdio> 2 #include<iostream> 3 #include<string.h> 4 using namespace std; 5 char num[100]; 6 const double INF = 100000000.0; 7 double prase_(char num[]){ 8 int len = strlen(num); 9 int pos = -1, cnt = 0; 10 int tag = 0; 11 for(int i = 0; num[i] != ' '; i++){ 12 if(!(num[i] >= '0' && num[i] <= '9' || num[i] == '.' || num[i] == '-')){ 13 return INF; 14 } 15 if(num[i] == '.') 16 cnt++; 17 if(cnt > 1) 18 return INF; 19 } 20 if(num[0] == '-') 21 tag = 1; 22 for(pos = 0; num[pos] != '.' && num[pos] != ' '; pos++); 23 int P = 1, ansL = 0, ansR = 0; 24 if(pos == ' '){ 25 for(int i = len - 1; i >= tag; i--){ 26 ansL += (num[i] - '0') * P; 27 P *= 10; 28 } 29 if(tag == 1) 30 return ansL * -1.0; 31 else return ansL * 1.0; 32 }else{ 33 if(len - pos - 1 > 2) 34 return INF; 35 P = 1; ansL = 0; 36 for(int i = pos - 1; i >= tag; i--){ 37 ansL += (num[i] - '0') * P; 38 P *= 10; 39 } 40 P = 1; ansR = 0; 41 for(int i = len - 1; i > pos; i--){ 42 ansR += (num[i] - '0') * P; 43 P *= 10; 44 } 45 double temp = ansR * 1.0; 46 for(int i = 0; i < len - pos - 1; i++){ 47 temp *= 0.1; 48 } 49 if(tag == 1) 50 return ((double)ansL + temp) * -1.0; 51 else return (double)ansL + temp; 52 } 53 } 54 int main(){ 55 int N, cnt = 0; 56 double sum = 0, temp = 0; 57 scanf("%d", &N); 58 for(int i = 0; i < N; i++){ 59 scanf("%s", num); 60 temp = prase_(num); 61 if(temp > 1000.0 || temp < -1000.0){ 62 printf("ERROR: %s is not a legal number ", num); 63 }else{ 64 sum += temp; 65 cnt++; 66 } 67 } 68 if(cnt > 1){ 69 double prt = sum / (double)cnt; 70 printf("The average of %d numbers is %.2f ", cnt, prt); 71 }else if (cnt == 0){ 72 printf("The average of 0 numbers is Undefined "); 73 }else if(cnt == 1){ 74 double prt = sum / (double)cnt; 75 printf("The average of %d number is %.2f ", cnt, prt); 76 } 77 cin >> N; 78 return 0; 79 }