How does the printf work?

Printf working principle Printf takes multiple arguments using vararg function. Like printf(“Hello, my name is \%s having an id \%d”, name, id); Printf creates an internal buffer for constructing output string. Now printf iterates through each characters of user string and copies the character to the output string.

What is the output if 1 printf hello );?

hello is the output. it will print hello, because in if statement the condition is printf(“hello”) so as per C compiler and according to operator precedence and if it see printf statement in condition place it will print the statement which is present in it.

How does printf work in assembly?

Printf in Assembly To call printf from assembly language, you just pass the format string in rdi as usual for the first argument, pass any format specifier arguments in the next argument register rsi, then rdx, etc.

How does Scanf work internally?

4 Answers. scanf() and printf() are functions in libc (the C standard library), and they call the read() and write() operating system syscalls respectively, talking to the file descriptors stdin and stdout respectively (fscanf and fprintf allow you to specify the file stream you want to read/write from).

Can printf be nested?

So, when multiple printf’s appear inside another printf, the inner printf prints its output and returns length of the string printed on the screen to the outer printf.

Does printf return a value?

printf returns an integer value, which is the total number of printed characters. For example: if you are printing “Hello” using printf, printf will return 5.

Can we write printf inside if condition?

The expression within if( expression ) is always evaluated, and in your case that’s a call to printf . The value of this expression is used to determine if the body (blank in your case) of the if is run. printf() function return the number of characters that are printed.

How many times does the program print Hello?

So “hello” will be printed 5 times.