仍在努力解决这个问题。需要找到输入数据的最小值，最大值和平均值，并将其打印到外部数据文件。任何人都可以在我的代码中发现问题它不打印任何东西。
需要读取具有以下内容的文件
min:1,2,3,4,5,6
max:1,2,3,4,5,6
avg:1,2,3,4,5,6
但需要以下列格式打印出来
The min of [1, 2, 3, 5, 6] is 1.
The max of [1, 2, 3, 5, 6] is 6.
The avg of [1, 2, 3, 5, 6] is 3.4.
public class Test {
public static void main(String[] args) throws IOException {
FileInputStream fi = new FileInputStream("F:\\Test\\file.txt");
FileOutputStream fo = new FileOutputStream("F:\\Test\\output.txt");
BufferedReader br = new BufferedReader(new InputStreamReader(fi));
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(fo));
String strLine;
while ((strLine = br.readLine()) != null) {
String[] arr = strLine.split(" ");
String[] nos = arr[1].split(",");
Set<Integer> set = new HashSet<Integer>();
for(int i = 0; i<nos.length; i++){
int no = Integer.parseInt(nos[i]);
set.add(no);
}
TreeSet<Integer> sortedSet = new TreeSet<Integer>(set);
switch(arr[0]) {
case "Min:":
String msg1="The Min of [" +arr[1]+ "] is " +(Integer)sortedSet.first();
bw.write(msg1);
bw.newLine();
break;
case "Max:":
String msg2="The Max of [" +arr[1]+ "] is " +(Integer)sortedSet.last();
bw.write(msg2);
bw.newLine();
break;
case "Avg:":
Object[] noarray = sortedSet.toArray();
int noarraysize = noarray.length-1;
int sum=0;
for(int i=0;i<=noarraysize;i++) {
int no=Integer.valueOf(noarray[i].toString());
sum = sum + no;
if(i==noarraysize) {
String msg3="The Avg of [" +arr[1]+ "] is " +(double)sum/noarray.length;
bw.write(msg3);
bw.newLine();
}
}
break;
case "Sum:":
Object[] noarray1 = sortedSet.toArray();
int noarraysize1 = noarray1.length-1;
int sum1=0;
for(int i=0;i<=noarraysize1;i++) {
int no=Integer.valueOf(noarray1[i].toString());
sum1 = sum1 + no;
if(i==noarraysize1) {
String msg4="The Sum of [" +arr[1]+ "] is " +sum1;
bw.write(msg4);
bw.newLine();
}
}
break;
}
}
br.close();
bw.close();
}
}
如果我在代码体之外添加一个print语句，它可以工作，但我输入的消息都不会从外部打印到文本文件中。
答案 0 :(得分：0)
这一行看起来是你的第一个问题：
String[] nos = arr[1].split(",");
arr只包含一个元素，因此您可以在数组边界外访问（记住数组是0索引的，因此第一个元素是arr [0]）。
你还有另一个问题：
int no = Integer.parseInt(nos[i]);
在尝试从输入中解析int之前，您需要使用输入的min:部分。
编辑进行了一些更改，使其与您提供的输入一起使用：
public static void main(String[] args) throws IOException {
FileInputStream fi = new FileInputStream("file.txt");
FileOutputStream fo = new FileOutputStream("output.txt");
BufferedReader br = new BufferedReader(new InputStreamReader(fi));
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(fo));
String strLine;
while ((strLine = br.readLine()) != null) {
String[] arr = strLine.split(":");
String[] nos = arr[1].split(",");
Set<Integer> set = new HashSet<Integer>();
for(int i = 0; i<nos.length; i++){
int no = Integer.parseInt(nos[i]);
set.add(no);
}
TreeSet<Integer> sortedSet = new TreeSet<Integer>(set);
switch(arr[0]) {
case "min":
String msg1="The Min of [" +arr[1]+ "] is " +(Integer)sortedSet.first();
bw.write(msg1);
bw.newLine();
break;
case "max":
String msg2="The Max of [" +arr[1]+ "] is " +(Integer)sortedSet.last();
bw.write(msg2);
bw.newLine();
break;
case "avg":
Object[] noarray = sortedSet.toArray();
int noarraysize = noarray.length-1;
int sum=0;
for(int i=0;i<=noarraysize;i++) {
int no=Integer.valueOf(noarray[i].toString());
sum = sum + no;
if(i==noarraysize) {
String msg3="The Avg of [" +arr[1]+ "] is " +(double)sum/noarray.length;
bw.write(msg3);
bw.newLine();
}
}
break;
case "sum":
Object[] noarray1 = sortedSet.toArray();
int noarraysize1 = noarray1.length-1;
int sum1=0;
for(int i=0;i<=noarraysize1;i++) {
int no=Integer.valueOf(noarray1[i].toString());
sum1 = sum1 + no;
if(i==noarraysize1) {
String msg4="The Sum of [" +arr[1]+ "] is " +sum1;
bw.write(msg4);
bw.newLine();
}
}
break;
}
}
br.close();
bw.close();
}