Roberto trevino14 comments
In this C programming language tutorial we take another look at the printf function. We will look at how to use format specifiers to print formatted output onto the screen. The topics covered are; a little printf background, format specifiers and conversions, formatting of different types and format conversions of strings.
The printf function is not part of the C language, because there is no input or output defined in C language itself. The printf function is just a useful function from the standard library of functions that are accessible by C programs. The behavior of printf is defined in the ANSI standard. Default argument promotions happen in variadic functions. Variadic functions are functions e.
When a variadic function is called, after lvalue-to-rvalue, array-to-pointer, and function-to-pointer conversions, each argument that is a part of the variable argument list undergoes additional conversions known as default argument promotions:. If you actually needed to pass, for example, a char instead of an int, the function would have to convert it back.
As you can see in the first printf statement we print a decimal. In the third printf statement we say almost the same as the previous one. Print the output with a width of three digits, but fill the space with 0. In the fourth printf statement we want to print a float. In this printf statement we want to print three position before the decimal point called width and two positions behind the decimal point called precision.
In this case it represents a newline character. After printing something to the screen you usually want to print something on the next line. Commonly used escape sequences are:. As you can see we print the Fahrenheit temperature with a width of 3 positions. The Celsius temperature is printed with a width of 6 positions and a precision of 3 positions after the decimal point. Until now we only used integers and floats, but there are more types you can use. Take a look at the following example:.
So if you want to print a percentage number you would use something like this: By now you have seen most of the format conversion possible, but there is one type that is a little different and that are string format conversions.
As you can see, the string format conversion reacts very different from number format conversions. The printf function uses its first argument to determine how many arguments will follow and of what types they are. Just make some examples of your own, they are easy to make. This is the only way to learn and see how the format conversions reacts. I found a very good tutorial here. This is very helpful… I like it very much, I hope this will be benificial for everyone………. I need to print out a float containing a GPS coordinate in decimal values, which is Is there any way to print the value as well as parsing the float into a string while keeping the precision?
I need to print something in the format 0. Normal scientific notation e. I hope you realize that unless your GPS is accurate to 3 meters, you are not going to actually have 3 meters of accuracy, regardless of how many decimal points it reports. Regarding your storage issue. Single precision floats have at most 6 to 9 decimal digits of precision.
When converting to a string, you are essentially generating a decimal representation of that float. So, in your case, you have an 8 digit decimal number that you first convert to float, then back to decimal in string form. You should expect that at most, the first 6 digits will match. In you second example, you used atoi which converts an ascii string to an integer. Integers are whole numbers. So, the output is exactly what you should have gotten. This article solved all my doubts, thank you so much.
The string part is also very clearly explained. Does this compile at all?! What do you want to reach with this? You add a constant to a format string! The application may crash or you get garbage. The innermost printf is parsed first producing the string which is printed out. The result is then also passed to the middle printf which actually prints right after the previous result the length number of digits of the innermost string i.
Then the outermost printf prints the length of this string i. Therefore the result is Can anyone plzz tell me the forma t specifier if the number is 1. Format Specifiers There are many format specifiers defined in C. Take a look at the following list: When a variadic function is called, after lvalue-to-rvalue, array-to-pointer, and function-to-pointer conversions, each argument that is a part of the variable argument list undergoes additional conversions known as default argument promotions: This entry was posted in C Tutorials.
You can follow any responses to this entry through the RSS 2. Both comments and pings are currently closed. This really helped me with my exam preparations. Haris on December 5th, They are very helpful for us. Subbu on January 18th, Steve on April 14th, Steve, I hope you realize that unless your GPS is accurate to 3 meters, you are not going to actually have 3 meters of accuracy, regardless of how many decimal points it reports. Prateek on May 31st, Kunal on June 10th, What is the role of C?
What are the various features of C Language. Lilian on September 10th, Ok Men, very good!!!! Sumithra on September 11th, Plz i need some programs regarding Format specifier…can yew guys help me in that… Amey Chaware on October 2nd, Steven Nguyen on October 3rd, How to print large number in the format , ,? It is very useful for me harish on December 17th, Use the shortest representation: Giridhar on January 29th, Is there a way to format an integer including the sign in the positive case, i.
Hamza saghir on March 23rd,