What is the prototype of printf function in c language?

Answer 1

int printf(const char * format, ...);

Answer 2

int printf( const char *format ,…);

'format' is constant character string, and '.....' indicates there may be variable number of arguments.

Answer 3

If you are using linux system.

Then You can execute "man 3 printf"
or for any C api you wanted to know.

man 2 --> for system calls (functions provided by the kernel)
man 3 --> for library calls (functions provided by the kernel)