What is the difference between printf and puts in C

Question

I know you can print with printf   and puts    I can also see that printf   allows you to interpolate variables and do formatting   Is puts   merely a primitive version of printf    Should it be used for every possible printf   without string interpolation

User · Answer

This is pointed out in a comment by Zan Lynx  but I think it deserves an aswer - given that the accepted answer doesn t mention it    The essential difference between puts mystr   and printf mystr   is that in the latter the argument is interpreted as a formatting string  The result will be often the same  except for the added newline  if the string doesn t contain any control characters     but if you cannot rely on that  if mystr is a variable instead of a literal   you should  not use it   So  it s generally dangerous -and conceptually wrong- to pass a dynamic string as single argument of printf      char   myMessage           myMessage gets assigned at runtime  unpredictable content   printf myMessage        lt --- WRONG   what if myMessage contains a     char      puts myMessage         ok   printf   s n  myMessage      ok  equivalent to the previous  perhaps less efficient   The same applies to fputs vs fprintf  but fputs doesn t add the newline

User · Answer

In simple cases  the compiler converts calls to printf   to calls to puts     For example  the following code will be compiled to the assembly code I show next    include  lt stdio h gt  main         printf  Hello world         return 0        push rbp mov rbp rsp mov edi str Helloworld  call dword imp puts mov eax 0x0 pop rbp ret   In this example  I used GCC version 4 7 2 and compiled the source with gcc -o hello hello c

User · Answer

the printf   function is used to print both strings and variables to the screen  while the puts   function only permits you to print a string only to your screen

User · Answer

int puts const char  s     puts   writes the string s and a trailing newline to stdout   int printf const char  format          The function printf   writes output to stdout  under the control of a format string that specifies how subsequent arguments are converted for output   I ll use this opportunity to ask you to read the documentation

User · Answer

puts is the simple choice and adds a new line in the end and printfwrites the output from a formatted string   See the documentation for puts  and for printf    I would recommend to use only printf as this is more consistent than switching method  i e if you are debbugging it is less painfull to search all printfs than puts and printf  Most times you want to output a variable in your printouts as well  so puts is mostly used in example code

User · Answer

Right  printf could be thought of as a more powerful version of puts  printf provides the ability to format variables for output using format specifiers such as  s   d   lf  etc

User · Answer

When comparing puts   and printf    even though their memory consumption is almost the same  puts   takes more time compared to printf

User · Answer

Besides formatting  puts returns a nonnegative integer if successful or EOF if unsuccessful  while printf returns the number of characters printed  not including the trailing null

User · Answer

In my experience  printf   hauls in more code than puts   regardless of the format string     If I don t need the formatting  I don t use printf   However  fwrite to stdout works a lot faster than puts   static const char my text      Using fwrite  n   fwrite my text  1  sizeof my text  - sizeof   0    stdout     Note  per comments    0  is an integer constant   The correct expression should be sizeof char  as indicated by the comments

User · Answer

puts is simpler than printf but be aware that the former automatically appends a newline   If that s not what you want  you can fputs your string to stdout or use printf

[c] What is the difference between printf() and puts() in C?

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