1. 编写一个程序，输出一个字符串中的大写英文字母个数，小写英文字母个数以及非英文字母个数.
第一种方法：
public class Test {
public static void main(String[] args) {
String s = "AaabbcceeeFgFhjklOIU9890454jiaQQqwq_!!!@09&&&haAA";
int Lcount = 0, Ucount = 0, Ocount = 0;
for(int i=0;i<s.length();i++){
if(s.charAt(i) >= ‘a‘ && s.charAt(i) <= ‘z‘){
Lcount++;
}
else if(s.charAt(i) >= ‘A‘ && s.charAt(i) <= ‘Z‘){
Ucount++;
}
else {
Ocount++;
}
}
System.out.println("Lcount: "+Lcount+","+"Ucount: "+Ucount+","+"Ocount: "+Ocount);
}
} //Lcount: 22,Ucount: 10,Ocount: 17
第二种方法：
public class Test {
public static void main(String[] args) {
String s = "AaabbcceeeFgFhjklOIU9890454jiaQQqwq_!!!@09&&&haAA";
int Lcount = 0, Ucount = 0, Ocount = 0;
for(int i=0;i<s.length();i++){
if(Character.isLowerCase(s.charAt(i))){
Lcount++;
}
else if(Character.isUpperCase(s.charAt(i))){
Ucount++;
}
else {
Ocount++;
}
}
System.out.println("Lcount: "+Lcount+","+"Ucount: "+Ucount+","+"Ocount: "+Ocount);
}
}// Lcount: 22,Ucount: 10,Ocount: 17
第三种方法：
public class Test {
public static void main(String[] args) {
String BL = "abcdefghijklmnopqrstuvwxyz";
String BU = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
String s = "AaabbcceeeFgFhjklOIU9890454jiaQQqwq_!!!@09&&&haAA";
int Lcount = 0, Ucount = 0, Ocount = 0;
for(int i=0;i<s.length();i++){
if(BL.indexOf(s.charAt(i)) != -1){
Lcount++;
}
else if(BU.indexOf(s.charAt(i)) != -1){
Ucount++;
}
else {
Ocount++;
}
}
System.out.println("Lcount: "+Lcount+","+"Ucount: "+Ucount+","+"Ocount: "+Ocount);
}
}// Lcount: 22,Ucount: 10,Ocount: 17
原文：http://www.cnblogs.com/bosongokay/p/6758906.html