Question:What is the difference between printf() and sprintf() ? 

sprintf() writes data to the character array whereas printf(...) writes data to the standard output device.

Question:What is the difference between %d and %*d in c language? 

%d give the original value of the variable and %*d give the address of the variable.

eg:-int a=10,b=20;
printf("%d%d",a,b);
printf("%*d%*d",a,b);

Result is 10 20 1775 1775 .Here 1775 is the starting address of the memory allocation for the integer.a and b having same address because of contagious memory allocation.

Question:What is FILE? 

FILE is a predefined data type. It is defined in stdio.h file.

Question:What is a file? 

A file is a region of storage in hard disks or in auxiliary storage devices.It contains bytes of information .It is not a data type.