1054 求平均值
本题的基本要求非常简单:给定 N 个实数,计算它们的平均值。但复杂的是有些输入数据可能是非法的。一个“合法”的输入是 [−1000,1000] 区间内的实数,并且最多精确到小数点后 2 位。当你计算平均值的时候,不能把那些非法的数据算在内。
输入格式:
输入第一行给出正整数 N(≤100)。随后一行给出 N 个实数,数字间以一个空格分隔。
输出格式:
对每个非法输入,在一行中输出 ERROR: X is not a legal number
,其中 X
是输入。最后在一行中输出结果:The average of K numbers is Y
,其中 K
是合法输入的个数,Y
是它们的平均值,精确到小数点后 2 位。如果平均值无法计算,则用 Undefined
替换 Y
。如果 K
为 1,则输出 The average of 1 number is Y
。
输入样例 1:
tex
7
5 -3.2 aaa 9999 2.3.4 7.123 2.35
7
5 -3.2 aaa 9999 2.3.4 7.123 2.35
输出样例 1:
tex
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
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
输入样例 2:
tex
2
aaa -9999
2
aaa -9999
输出样例 2:
tex
ERROR: aaa is not a legal number
ERROR: -9999 is not a legal number
The average of 0 numbers is Undefined
ERROR: aaa is not a legal number
ERROR: -9999 is not a legal number
The average of 0 numbers is Undefined
Solution:
java
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class Main {
public static void main(String[] args) throws IOException {
BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
int n = Integer.parseInt(in.readLine());
String[] a = in.readLine().split(" ");
double sum = 0;
double X = 0;
int K = 0;
for (String s : a) {
try {
X = Double.parseDouble(s);
String str = String.valueOf(X);
if (X >= -1000 && X <= 1000 && str.substring(str.indexOf(".")).length() <= 3) {
sum += X * 100;
K++;
} else
System.out.println("ERROR: " + s + " is not a legal number");
} catch (NumberFormatException e) {
System.out.println("ERROR: " + s + " is not a legal number");
}
}
if (K >= 1)
System.out.println("The average of " + K + (K == 1 ? " number is " : " numbers is ")
+ String.format("%.2f", sum / K / 100));
else
System.out.println("The average of " + K + " numbers is Undefined");
}
}
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class Main {
public static void main(String[] args) throws IOException {
BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
int n = Integer.parseInt(in.readLine());
String[] a = in.readLine().split(" ");
double sum = 0;
double X = 0;
int K = 0;
for (String s : a) {
try {
X = Double.parseDouble(s);
String str = String.valueOf(X);
if (X >= -1000 && X <= 1000 && str.substring(str.indexOf(".")).length() <= 3) {
sum += X * 100;
K++;
} else
System.out.println("ERROR: " + s + " is not a legal number");
} catch (NumberFormatException e) {
System.out.println("ERROR: " + s + " is not a legal number");
}
}
if (K >= 1)
System.out.println("The average of " + K + (K == 1 ? " number is " : " numbers is ")
+ String.format("%.2f", sum / K / 100));
else
System.out.println("The average of " + K + " numbers is Undefined");
}
}