Function Printf Dev C++
For the input of specific types of variables in the C programming language, you’ll find that the scanf() function comes in handy. It’s not a general-purpose input function, and it has some limitations, but it’s great for testing code or grabbing values.
Depending on the format string, the function may expect a sequence of additional arguments, each containing a value to be used to replace a format specifier in the format string (or a pointer to a storage location, for n). There should be at least as many of these arguments as the number of values specified in the format specifiers. Additional arguments are ignored by the function. C: Single character: Reads the next character. If a width different from 1 is specified, the function reads width characters and stores them in the successive locations of the array passed as argument. No null character is appended at the end. Char. d: Decimal integer: Number optionally preceded with a + or - sign: int. e, E, f, g, G. Oct 21, 2006 What does printf do? C / C Forums on Bytes. I have a question: what does printf do? I have seen it a lot, but cannot find a clear description of what it does. In my learn c in 21 days book, it states that it will not teach it in the book. Thanks, -Brad.
In a way, you could argue that scanf() is the input version of the printf() function. For example, it uses the same conversion characters (the % placeholder-things). Because of that, scanf() is quite particular about how text is input. Here’s the format:
Scary, huh? Just ignore it for now. Here’s a less frightening version of the format:
C code snippet to print value in decimal, octal and hexadecimal using printf function in c, printf with format specifier. A humble request Our website is made possible by displaying online advertisements to our visitors. Once a function pragma is seen, it takes effect at the first function definition that contains a specified intrinsic function. The effect continues to the end of the source file, or to the appearance of an intrinsic pragma specifying the same intrinsic function.
In this version, placeholder is a conversion character, and variableXfer serum presets. is a type of variable that matches the conversion character. Unless it’s a string (char array), the variable is prefixed by the & operator.
The scanf() function is prototyped in the stdio.h header file, so you must include that file when you use the function.
Cannot delete partition on mac. Here are some scanf() examples:
The preceding statement reads an integer value into the variable highscore. This assumes that highscore is an int variable.
The preceding scanf() statement waits for a floating-point value to be input, which is then stored in the temperature variable.
In the preceding line, scanf() accepts the first character input and stores it in the key variable.
The %s placeholder is used to read in text, but only until the first white space character is encountered. So a space or a tab or the Enter key terminates the string. (That sucks.) Also, firstname is a char array, so it doesn’t need the & operator in the scanf() function.
How to read a string with scanf()
One of the most common ways to put the scanf() function to use is to read in a chunk of text from standard input. To meet that end, the %s conversion character is used — just like in printf(), but with input instead of output.
SCANF() SWALLOWS A STRING
Exercise 1: Type the source code from scanf() Swallows a String into a new project, ex0712, in Code::Blocks. Build and run.
Line 5 declares a char array — a string variable — named firstname. The number in the brackets indicates the size of the array, or the total number of characters that can be stored there. The array isn’t assigned a value, so it’s created empty. Basically, the statement at Line 5 sets aside storage for up to 15 characters.
The scanf() function in Line 8 reads a string from standard input and stores it in the firstname array. The %s conversion character directs scanf() to look for a string as input, just as %s is a placeholder for strings in printf()’s output.
Exercise 2: Modify the source code from scanf() Swallows a String so that a second string is declared for the person’s last name. Prompt the user for their last name as well, and then display both names by using a single printf() function.
The number in the brackets (refer to Line 5) gives the size of the char array, or the length of the string, plus one.
When you create a char array, or string variable, ensure that you create it of a size large enough to hold the text. That size should be the maximum number of characters plus one.
The reason for increasing the char array size by one is that all strings in C end with a specific termination character. It’s the NULL character, which is written as . The compiler automatically adds the to the end of string values you create in your source code, as well as text read by various text-input functions.
You must remember to add room for that character when you set aside storage for string input.
How to read values with scanf()
The scanf() function can do more than read strings. It can read in any value specified by a conversion character.
SCANF() EATS AN INTEGER
In scanf() Eats an Integer, the scanf() function reads in an integer value. The %d conversion character is used, just like printf() — indeed, it’s used in Line 9. That character directs scanf() to look for an int value for variable fav.
Exercise 3: Create a project, ex0714, using the source code shown in scanf() Eats an Integer. Build and run. Test the program by typing various integer values, positive and negative.
Perhaps you’re wondering about the ampersand (&) in the scanf() function. The character is a C operator — specifically, the memory address operator. It’s one of the advanced features in C that’s related to pointers. An ampersand must prefix any variable specified in the scanf() function. The exception is an array, such as the firstname char array in scanf() Eats an Integer.
Try running the program again, but specify a decimal value, such as 41.9, or type text instead of a number.
The reason you see incorrect output is that scanf() is very specific. It fetches only the variable type specified by the conversion character. So if you want a floating-point value, you must specify a float variable and use the appropriate conversion character; %f, in that case.
Exercise 4: Modify the source code from scanf() Eats an Integer so that a floating-point number is requested, input, and displayed.
You don’t need to prefix a char array variable with an ampersand in the scanf() function; when using scanf() to read in a string, just specify the string variable name.
The scanf() function stops reading text input at the first white space character, space, tab, or Enter key.
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printf()
This is mainly used in C language. It is a formatting function that prints to the standard out. It prints to the console and takes a format specifier to print. It returns an integer value. It is not type safe in input parameters. It can be used in C++ language too.
Here is the syntax of printf() in C and C++ language,
Here,
String − Any text/message to print on console.
Format Specifier − According to the variable datatype, use format specifiers like %d, %s etc.
variable_name − Any name given to declare the variable.
Here is an example of printf() in C language,
Example
Here is the output
cout
This is used in C++ language. It is an object of iostream in C++ language. It also prints to the console. It does not take any format specifier to print. It does not return anything. It is type safe in input parameters.
Here is the syntax of cout in C++ language,
Here,
string − Any text/message to print on console.
variable_name − Any name given to the variable at the time of declaration.
Here is an example of cout in C++ language,
Dev C++ For Windows 10
Example
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Here is the output