How do I read a string entered by the user in C

Question

I want to read the name entered by my user using C programmes   For this I wrote   char name 20    printf  Enter name      gets name     But using gets is not good  so what is a better way

User · Answer

Using scanf removing any blank spaces before the string is typed and limiting the amount of characters to be read    define SIZE 100        char str SIZE    scanf    99   n    str       Or even you can do it like this     scanf    99 a-zA-Z0-9     str     If you do not limit the amount of characters to be read with scanf it can be as dangerous as gets

User · Answer

I think the best and safest way to read strings entered by the user is using getline    Here s an example how to do this    include  lt stdio h gt   include  lt stdlib h gt  int main int argc  char  argv          char  buffer   NULL      int read      unsigned int len      read   getline  amp buffer   amp len  stdin       if  -1    read          puts buffer       else         printf  No line read    n         printf  Size read   d n Len   d n   read  len       free buffer       return 0

User · Answer

I found an easy and nice solution   char string acquire char s int size FILE stream       int i      fgets s size stream       i strlen s -1      if s i     n   while getchar      n        if s i     n   s i    0       return s      it s based on fgets but free from   n  and stdin extra characters  to replace fflush stdin  that doesn t works on all OS  useful if you have to acquire strings after this

User · Answer

You should never use gets  or scanf with an unbounded string size  since that opens you up to buffer overflows  Use the fgets with a stdin handle since it allows you to limit the data that will be placed in your buffer   Here s a little snippet I use for line input from the user    include  lt stdio h gt   include  lt string h gt    define OK       0  define NO INPUT 1  define TOO LONG 2 static int getLine  char  prmpt  char  buff  size t sz        int ch  extra          Get line with buffer overrun protection      if  prmpt    NULL            printf    s   prmpt           fflush  stdout             if  fgets  buff  sz  stdin     NULL          return NO INPUT          If it was too long  there ll be no newline  In that case  we flush        to end of line so that excess doesn t affect the next call      if  buff strlen buff -1       n             extra   0          while    ch   getchar         n    amp  amp   ch    EOF               extra   1          return  extra    1    TOO LONG   OK                Otherwise remove newline and give string back to caller      buff strlen buff -1      0       return OK      This allows me to set the maximum size  will detect if too much data is entered on the line  and will flush the rest of the line as well so it doesn t affect the next input operation   You can test it with something like      Test program for getLine     int main  void        int rc      char buff 10        rc   getLine   Enter string gt     buff  sizeof buff        if  rc    NO INPUT               Extra NL since my system doesn t output that on EOF          printf    nNo input n            return 1             if  rc    TOO LONG            printf   Input too long   s  n   buff           return 1             printf   OK   s  n   buff        return 0

User · Answer

On BSD systems and Android you can also use fgetln    include  lt stdio h gt   char   fgetln FILE  stream  size t  len     Like so   size t line len  const char  line   fgetln stdin   amp line len     The line is not null terminated and contains  n  or whatever your platform is using  in the end  It becomes invalid after the next I O operation on stream  You are allowed to modify the returned line buffer

User · Answer

On a POSIX system  you probably should use getline if it s available   You also can use Chuck Falconer s public domain ggets function which provides syntax closer to gets but without the problems   Chuck Falconer s website is no longer available  although archive org has a copy  and I ve made my own page for ggets

User · Answer

You can use scanf function to read string          scanf      n   name     i don t know about other better options to receive string

[c] How do I read a string entered by the user in C?

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