The following rather meaningless program illustrates various of the string and character manipulation methods that are available in Java and which will be found to be useful in developing translators. The methods are closely related to those illustrated in C# later on this page, but they are not always completely equivalent.
import java.util.*;
class Demo {
public static void main(String[] args) {
char c, c1, c2;
boolean b, b1, b2;
String s, s1, s2;
int i, i1, i2;
b = Character.isLetter(c); // true if letter
b = Character.isDigit(c); // true if digit
b = Character.isLetterOrDigit(c); // true if letter or digit
b = Character.isWhitespace(c); // true if white space
b = Character.isLowerCase(c); // true if lowercase
b = Character.isUpperCase(c); // true if uppercase
c = Character.toLowerCase(c); // equivalent lowercase
c = Character.toUpperCase(c); // equivalent uppercase
s = Character.toString(c); // convert to string
i = s.length(); // length of string
b = s.equals(s1); // true if s == s1
b = s.equalsIgnoreCase(s1); // true if s == s1, case irrelevant
i = s1.compareTo(s2); // i = -1, 0, 1 if s1 < = > s2
s = s.trim(); // remove leading/trailing whitespace
s = s.toUpperCase(); // equivalent uppercase string
s = s.toLowerCase(); // equivalent lowercase string
char[] ca = s.toCharArray(); // create character array
s = s1.concat(s2); // s1 + s2
s = s.substring(i1); // substring starting at s[i1]
s = s.substring(i1, i2); // substring s[i1 ... i2-1]
s = s.replace(c1, c2); // replace all c1 by c2
c = s.charAt(i); // extract i-th character of s
// s[i] = c; // not allowed
i = s.indexOf(c); // position of c in s[0 ...
i = s.indexOf(c, i1); // position of c in s[i1 ...
i = s.indexOf(s1); // position of s1 in s[0 ...
i = s.indexOf(s1, i1); // position of s1 in s[i1 ...
i = s.lastIndexOf(c); // last position of c in s
i = s.lastIndexOf(c, i1); // last position of c in s, <= i1
i = s.lastIndexOf(s1); // last position of s1 in s
i = s.lastIndexOf(s1, i1); // last position of s1 in s, <= i1
i = Integer.parseInt(s); // convert string to integer
i = Integer.parseInt(s, i1); // convert string to integer, base i1
s = Integer.toString(i); // convert integer to string
StringBuffer // build strings (Java 1.4)
sb = new StringBuffer(), //
sb1 = new StringBuffer("original"); //
StringBuilder // build strings (Jaba 1.5 and 1.6)
sb = new StringBuilder(), //
sb1 = new StringBuilder("original"); //
sb.append(c); // append c to end of sb
sb.append(s); // append s to end of sb
sb.insert(i, c); // insert c in position i
sb.insert(i, s); // insert s in position i
sb.reverse(); // reverse sb (no equivalent in C# it seems)
b = sb.equals(sb1); // true if sb == sb1
i = sb.length(); // length of sb
i = sb.indexOf(s1); // position of s1 in sb
sb.delete(i1, i2); // remove sb[i1 .. i2-1]
sb.deleteCharAt(i1); // remove sb[i1]
sb.replace(i1, i2, s1); // replace sb[i1 .. i2-1] by s1
s = sb.toString(); // convert sb to real string
c = sb.charAt(i); // extract sb[i]
sb.setCharAt(i, c); // sb[i] = c
StringTokenizer // tokenize strings
st = new StringTokenizer(s, ".,"); // delimiters are . and ,
st = new StringTokenizer(s, ".,", true); // delimiters are also tokens
while (st.hasMoreTokens()) // process successive tokens
process(st.nextToken());
String[] // tokenize strings
tokens = s.split(".;"); // delimiters are defined by a regexp
for (i = 0; i < tokens.length; i++) // process successive tokens
process(tokens[i]);
}
}
The following rather meaningless program illustrates various of the string and character manipulation methods that are available in C# and which will be found to be useful in developing translators. The methods are closely related to those illustrated in Java earlier on this page, but they are not always completely equivalent.
using System.Text; // for StringBuilder
using System; // for Char
class demo {
public static void Main(string[] args) {
char c, c1, c2;
bool b, b1, b2;
string s, s1, s2;
int i, i1, i2;
b = Char.IsLetter(c); // true if letter
b = Char.IsDigit(c); // true if digit
b = Char.IsLetterOrDigit(c); // true if letter or digit
b = Char.IsWhiteSpace(c); // true if white space
b = Char.IsLower(c); // true if lowercase
b = Char.IsUpper(c); // true if uppercase
c = Char.ToLower(c); // equivalent lowercase
c = Char.ToUpper(c); // equivalent uppercase
s = c.ToString(); // convert to string
i = s.Length; // length of string
b = s.Equals(s1); // true if s == s1
b = String.Equals(s1, s2); // true if s1 == s2
i = String.Compare(s1, s2); // i = -1, 0, 1 if s1 < = > s2
i = String.Compare(s1, s2, true); // i = -1, 0, 1 if s1 < = > s2, ignoring case
s = s.Trim(); // remove leading/trailing whitespace
s = s.ToUpper(); // equivalent uppercase string
s = s.ToLower(); // equivalent lowercase string
char[] ca = s.ToCharArray(); // create character array
s = String.Concat(s1, s2); // s1 + s2
s = s.Substring(i1); // substring starting at s[i1]
s = s.Substring(i1, i2); // substring s[i1 ... i1+i2-1] (i2 is length)
s = s.Remove(i1, i2); // remove i2 chars from s[i1]
s = s.Replace(c1, c2); // replace all c1 by c2
s = s.Replace(s1, s2); // replace all s1 by s2
c = s[i]; // extract i-th character of s
// s[i] = c; // not allowed
i = s.IndexOf(c); // position of c in s[0 ...
i = s.IndexOf(c, i1); // position of c in s[i1 ...
i = s.IndexOf(s1); // position of s1 in s[0 ...
i = s.IndexOf(s1, i1); // position of s1 in s[i1 ...
i = s.LastIndexOf(c); // last position of c in s
i = s.LastIndexOf(c, i1); // last position of c in s, <= i1
i = s.LastIndexOf(s1); // last position of s1 in s
i = s.LastIndexOf(s1, i1); // last position of s1 in s, <= i1
i = Convert.ToInt32(s); // convert string to integer
i = Convert.ToInt32(s, i1); // convert string to integer, base i1
s = Convert.ToString(i); // convert integer to string
StringBuilder // build strings
sb = new StringBuilder(), //
sb1 = new StringBuilder("original"); //
sb.Append(c); // append c to end of sb
sb.Append(s); // append s to end of sb
sb.Insert(i, c); // insert c in position i
sb.Insert(i, s); // insert s in position i
b = sb.Equals(sb1); // true if sb == sb1
i = sb.Length; // length of sb
sb.Remove(i1, i2); // remove i2 chars from sb[i1]
sb.Replace(c1, c2); // replace all c1 by c2
sb.Replace(s1, s2); // replace all s1 by s2
s = sb.ToString(); // convert sb to real string
c = sb[i]; // extract sb[i]
sb[i] = c; // sb[i] = c
char[] delim = new char[] {'a', 'b'};
string[] tokens; // tokenize strings
tokens = s.Split(delim); // delimiters are a and b
tokens = s.Split('.' ,':', '@'); // delimiters are . : and @
tokens = s.Split(new char[] {'+', '-'}); // delimiters are + -?
for (int i = 0; i < tokens.Length; i++) // process successive tokens
Process(tokens[i]);
}
}
Modified: 2010/09/10