字符串组成字符判断
/**
* 字符串中字符判断
*
*
*/
public class StringCheck {

public static void main(String[] args) {

String s = "A BC d90$2*() E";

int digitNum = 0;
int letterNum = 0;
int spaceNum = 0;
int otherNum = 0;

char[] chars = s.toCharArray();
for (int i = 0; i < chars.length; i++) {
char c = chars[i];

if (c >= '0' && c <= '9') {
digitNum++;
} else if ((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z')) {
letterNum++;
} else if (c == ' ') {
spaceNum++;
} else {
otherNum++;
}
}

System.out.println("字母个数是" + letterNum);
System.out.println("数字个数是" + digitNum);
System.out.println("空格个数是" + spaceNum);
System.out.println("其他字符个数" + otherNum);
}

}