If I have some non-defaulting linking instructions that I want Dev-C to hand on to TDM for compiling and linking, whereabouts in Dev-C do I go to add those in, so that they get saved and remembered? 1 year ago Durgarao posted a comment on ticket #177.sir,please provide dark theme for dev-c. Formatting Numbers with C Output Streams David Kieras, EECS Dept., Univ. Of Michigan Revised for EECS 381, Winter 2004. Using the output operator with C streams is generally easy as pie, with the only hard part being controlling the format of.

So we've learnt how to collect basic data from the user, but wouldn't it be useful if we could do different things depending on what the user typed in? Well this happens to be a very core concept of computer programming, and we can do exactly as previously described with these things called 'if' statements. These are basic statements which allow us to do certain things only in certain conditions.

If I initialize graphics in my program and then use cout the font appears bigger than normal and the cursor doesn't blink on the screen. Using cout with graphic screens Home. Programming Forum. Using square root in dev C. Post by jonsca and tux4life have divulged all the information related to this topic.But would like to add some from my side. Apart from the printable characters (character which can be seen on a output screen) we make use of several other operations when working on any text.

The first thing we're going to learn about is the 'if' itself. Just write the if keyword and then in some brackets, the condition. To specify the condition you simply write one value (either a variable or constant), then the comparison operator you want to compare them with (for example - equal to, which is ) and then the second value (either a variable or constant). We then put some curly brackets, and anything inside the curly brackets is what will be executed if the condition is true. For example, the following would compare 1 to 1 (which is a bit silly, but gives an example which is obviously always true):

Note that the value that you are comparing the second thing to must match the type of the first thing - for example, if comparing a string you must either compare to a string variable, or to a string constant (and remember that string constants are always shown in double quotes). In our example, however, one always equals one, so it's not much of a condition -- we can use variables to actually create a somewhat useful condition:

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In this case the program would output 'Wow, I'm 16 too!' if the user entered the value 16, but would not output anything if the user inputted any other number. We can also compare any two variables using the same method:

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The issue we have at the moment, is that in most programs we aren't always going to want to just check if something is equal to something else. What if we wanted to check if something was less than, or greater than, or not equal to something else? Well luckily there are other comparison operators we can use instead of just being restricted to the 'is equal to' operator (). 'Less Than' (<) and 'Greater Than' (>) are relatively simple - they are simply their usual symbols, and so we could check if the user's height is greater than their age like this:

We can also do 'Greater Than or Equal To' and 'Less Than or Equal To' by simply adding a single equals sign after the appropriate symbol. For example, we could check if the user's height was less than or equal to their age like this:

There are also the simple 'equal to' and 'not equal to' conditional operators. We already know 'equal to' as , and 'not equal to' is an exclamation mark followed by an equals sign: !=. So we could check if the user's height doesn't equal their age like so:

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Ok, so now that we can compare two values pretty well - what if we want to do a variety of things depending on different conditions? For example if we wanted to do one thing if their height and age were equal, and if they aren't then do something else if another condition is met. Well we can accomplish this using 'else if'. You can just write else if after your closing curly bracket for your original 'if' statement, and then specify your 'else if' condition followed by the curly brackets to contain the code to be executed if they are met. For example:

Notice that it's very easy just to string together 'if's and 'else if's, in this case I've just chained two 'else if's off my original 'if'. We can also specify something to do if none of the conditions are met (in our example above this wouldn't really be useful since it's impossible not to meet any of the conditions, but it's generally good practice to put an else in just in case something goes seriously wrong). We can do this using the else keyword, and then some curly brackets to specify the code that could be executed at the end of our 'daisy chain':

A great example of 'daisy chaining' these all up is to create a program which asks for a student's test score, and then spits out the grade that they got. Try and create such an application yourself and see how you do. One solution to the problem is as follows, however it's worth noting that repeating this much code should be making your 'bad code' sense tingle! It goes against the 'Don't Repeat Yourself' principle of programming, but for now, a solution like this will have to do:

When you open a file, all kinds of things can go wrong. A file lives on a physical device — a fixed disk, for example, or perhaps on a flash drive or SD card — and you can run into problems when working with physical devices.

For example, part of the disk might be damaged, causing an existing file to become corrupted. Or, less disastrous, you might run out of disk space. Or, even less disastrous, you might try to open a file in a directory that doesn’t exist.

If you try to open a file for writing by specifying a full path and filename but the directory does not exist, the computer responds differently, depending on the operating system you’re using. If you’re unsure how your particular operating system will respond, try writing a simple test application that tries to create and open something like /abc/def/ghi/jkl/abc.txt. (Of course, you’ll want to be sure to use a directory that doesn’t exist.)

Then one of two things will happen: Either the directory and the file will get created, or nothing will happen.

For example, on a Windows system, if we attempt to create a file in a directory that doesn’t exist, the system does not create the directory. That’s because deep down inside, the application ultimately calls an operating system function that does the dirty work of creating the file. And this particular operating system function (it’s called CreateFile(), if you even care) has a rule that it will not create a directory for you.

If you want to determine whether the ostream class was unable to create a file, you can call its fail() member function. This function returns true if the object couldn’t create the file. And that’s what happens when a directory doesn’t exist. The DirectoryCheck01 example shown demonstrates an example of this.

When you run this code, assuming that you don’t have a directory called /abc/def/ghi on your system, you should see the message Couldn’t open the file! Assuming that your particular operating system doesn’t create a directory in this case; if it does, your computer will open the file, write Hi to it, and move on with its happy life after closing things out.

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As an alternative to calling the fail() member function, you can use an operator available in various stream classes. This is !, fondly referred to as the “bang” operator, and you would use it in place of calling fail(), as in this code:

Most people prefer to use !outfile instead of outfile.fail(), although !outfile makes confusing code. The reason is that outfile is an object, and the notion of !outfile simply doesn’t make sense.

In fact, !outfile trips up many beginning programmers. They know that outfile is not a pointer in this sample code, and they wonder how you could test it against 0 as you normally can only do with a pointer. (Remember, by saying !x, where x is some pointer, you’re testing x against 0.) And that simply doesn’t make sense! And so, to avoid confusion, just call fail(). It makes more sense.

Here are some reasons your file creation may choke:

• The directory doesn’t exist.

• You’re out of disk space and out of luck.

• Your application doesn’t have the right permissions to create a file.

• The filename was invalid — that is, it contained characters the operating system doesn’t allow in a filename, such as * or ?.

Like any good application, your application should do two things:

1. 1.Check whether a file creation succeeded.

2. 2.If the file creation failed, handle it appropriately.

   Don’t just print a horrible message like Oops!Aborting!, leaving your poor users with no choice but to toss the monitor onto the floor. Instead, do something friendlier — such as presenting a message telling them there’s a problem and suggesting that they might free more disk space.