There are several ways. The most straightforward is: String myString = numString.trim(); int i = Integer.parseInt(myString); long l = Long.parseLong(myString) or String myString = numString.trim(); i = Integer.parseInt(myString,myIntRadix); Note 1: There is a gotcha with parseInt - it will throw a NumberFormatException for String values in the range "80000000" to "ffffffff". You might expect it to interpret them as negative, but it does not. The values have to be "-80000000" .

Try any of these: String s = String.valueOf(i); or String s = Integer.toString(i); or String s = Integer.toString(i, radix); or // briefer but may result in extra object allocation. String s = "" + i; Note: There are similar classes for Double, Float, Long, etc.

You want to make a function that converts from a type to another. Like from std::string to int, or the other way around. This can be done using std::stringstream and insertion / extraction operators. Just as above, templates will prove of great help: Its usage is not as straightforward as the above explained max template. Normally, you would want to call it like "int value = lexical_cast( myStdString );". There is, however, a problem.

In general, when you want to convert from one type to another, the first class to look at is System.Convert. It has a load of static methods which are likely to help you. If you're converting from a String, you could also check whether the type that you want to convert to has a Parse method or something similar - for instance, I usually use DateTime.ParseExact to convert from a String to a DateTime.

You can print the hex equivalent of an int with: int i = 0xf1; System.out.println("i is hex " + Integer.toHexString(i) );

Code like this seems to show that the calls don't work! String s = " hello "; s.trim(); s.toUpperCase(); Note again that Strings are immutable. This means that once a String has been initialized, its contents won't change. In the code above, the method calls return a different String with the desired alterations. But this new String is not assigned to anything, so the results are discarded. To see the changes, assign the results of the method call to the original String or to another String.

No. A String constant such as "" or "hello" is already a String, so there's no need to write code like: String s = new String(""); You can instead write the simpler String s = ""; Note that Strings are immutable (unchangeable), so there is no danger of accidentally modifying a String that is pointed to by another reference.

How to add a float (or "any" type really) to the end of a C++ string? Unlike routines like atoi mentioned in the previous question, there is no direct routine such as itoa available. However, similar to the string I/O routines in the previous question, one can do this: #include <stdio.h> // cstdio in C++ // ..

You use static members of the Convert class found in the System namespace to handle conversions in the .NET framework.

This is something you do a lot in programming and pretty much every language makes it easy to convert between types. You may have already printed integers to the console with COUT or PRINTF, which of course needs to be converted to a string first. Converting numbers to strings is done in a similar way. Boost is a C++ library that can help you with problems like these and many others.

I am including the header file <string>, and I am using the string class, but the code doesn't compile? (namespace resolution, having the std:: topics) How do I use unique() with vectors? (answered only once, but still a good question to have due to people not knowing that it's possible to do)

Package names are guaranteed uniqueness by using the Internet domain name in reverse order: com.javasoft.jag - the "com" or "edu" (etc.) part used to be in upper case, but now lower case is the recommendation. Class and interface names are descriptive nouns, with the first letter of each word capitalized: PolarCoords. Interfaces are often called "something-able", e.g. "Observable", "Runnable", "Sortable".

JDK 1.2 has System.setProperty( "property", "new value" ); Until then, you can get all the properties, and set just the one you want with code like this: System.getProperties().put("property", "new value" );

Use Runtime.getRuntime().exec( myCommandString ) where myCommandString is something like "/full/pathname/command". An applet will need to be signed in order to allow this. If the pathname contains spaces, e.g. "c:\program files\windows\notepad", then enclose it in quotes within the quoted string. Or pre-tokenize them into elements of an array and call exec(String[] cmd) instead of exec(String cmd). From JDK1.3 there are two new overloaded Runtime.exec() methods.

Use bytes, shorts, chars, ints or longs if you need to manipulate no more than 64 bits at once. Use ~ for NOT, & for AND, | for OR, and ^ for XOR. Beware that the precedence for & | and ^ is not intuitive; they have lower precedence than == and !=, so you must write: if ((a & 1) == 1) rather than: if (a & 1 == 1) You can also shift bits with the <<, >> and >>> operators; >> is a signed shift and >>> is an unsigned shift.

Look at the code below, submitted by expert programmer John Dumas. It uses serialization to write an object into a byte array, and reads it back to reconstitute a fresh copy. This is a clever hack! import java.io.ByteArrayOutputStream; import java.io.ByteArrayInputStream; import java.io.ObjectOutputStream; import java.io.

Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load Private Sub ddlCulture_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ddlCulture.SelectedIndexChanged

Well, printf does it for output, so look at its related function named sprintf that "prints formated output to a string."

It's easy. Use sprintf. For example: char string1[50]; char string2[50]; short int var1; float var2; ... sprintf (string1, "%d", var1); sprintf (string2, "%f", var2);