流式输入/输出 示例
/*wc( )方法对任何输入流进行操作并且计算字符数，行数和字数。它在lastNotWhite里追踪字数的奇偶和空格。当在没有参数的情况下执行时，WordCount以System.in为源流生成一个InputStreamReader对象。该流然后被传递到实际计数的 wc( )方法。当在有一个或多个参数的情况下执行时，WordCount 假设这些文件名存在并给每一个文件创建FileReader，传递保存结果的FileReader对象给wc( ) 方法。两种情况下，在退出之前都打印结果。
*/
//A word counting utility.
import java.io.*;
class WordCount{
public static int intWords = 0;
public static int intLines = 0;
public static int intChars = 0;
public static void wc(InputStreamReader isr) throws IOException{
int c = 0;
boolean lastWhite = true;
String whiteSpace = "\t\n\r";
while((c=isr.read())!=-1){
//Count characters.
intChars++;
//Count lines.
if(c=='\n'){
intLines++;
}
//Count words by detecting the start of a word
int intIndex = whiteSpace.indexOf(c);
if(intIndex == -1){
if(lastWhite == true){
++intWords;
}
lastWhite = false;
}else{
lastWhite = true;
}
}
if(intChars !=0){
++intLines;
}
}
public static void main(String[] args)
{
FileReader fr ;
try{
if(args.length ==0){
//We're working with stdin
wc(new InputStreamReader(System.in));
}else{
//We're working with a list of files.
for(int i=0;i<args.length;i++){
fr = new FileReader(args);
wc(fr);
}
}
}catch(IOException e){
return;
}
System.out.println(intLines + " " + intWords + " " + intChars);
}
}
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