How to do scanf for single char in C

Question

In C  I m trying to get char from the user with scanf and when I run it the program don t wait for the user to type anything     This is the code   char ch  printf  Enter one char    scanf   c    amp ch   printf   c n  ch     Why is not working

User · Answer

Here is a similiar thing that I would like to share,

while you're working on Visual Studio you could get an error like:

'scanf': function or variable may be unsafe. Consider using scanf_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS

To prevent this, you should write it in the following format

A single character may be read as follows:

char c;
scanf_s("%c", &c, 1);

When multiple characters for non-null terminated strings are read, integers are used as the width specification and the buffer size.

char c[4];
scanf_s("%4c", &c, _countof(c));

User · Answer

You have to use a valid variable  ch is not a valid variable for this program  Use char Aaa    char aaa  scanf   c   amp Aaa     Tested and it works

User · Answer

Use string instead of char like   char c 10   scanf    s   c     I belive it works nice

User · Answer

try using getchar    instead  syntax   void main         char ch      ch   getchar

User · Answer

This works for me try it out  int main    char c  scanf    c   amp c   printf   c  c   return 0

User · Answer

The only code that worked for me is   scanf    c   amp c     I was having the same problem  and only with single characters  After an hour of random testing I can not report an issue yet  One would think that C would have by now a bullet-proof function to retrieve single characters from the keyboard  and not an array of possible hackarounds    Just saying

User · Answer

Provides a space before  c conversion specifier so that compiler will ignore white spaces  The program may be written as below    include  lt stdio h gt   include  lt stdlib h gt  int main         char ch      printf  Enter one char        scanf    c    amp ch     Space is given before  c       printf   c n  ch   return 0

User · Answer

First of all  avoid scanf    Using it is not worth the pain   See  Why does everyone say not to use scanf  What should I use instead   Using a whitespace character in scanf   would ignore any number of whitespace characters left in the input stream  what if you need to read more inputs  Consider    include  lt stdio h gt   int main void       char ch1  ch2      scanf   c    amp ch1       Leaves the newline in the input       scanf    c    amp ch2      The leading whitespace ensures it s the                           previous newline is ignored       printf  ch1   c  ch2   c n   ch1  ch2          All good so far        char ch3     scanf   c    amp ch3      Doesn t read input due to the same problem       printf  ch3   c n   ch3       return 0      While the 3rd scanf   can be fixed in the same way using a leading whitespace  it s not always going to that simple as above  Another major problem is  scanf   will not discard any input in the input stream if it doesn t match the format  For example  if you input abc for an int such as  scanf   d    amp int var   then abc will have to read and discarded  Consider    include  lt stdio h gt   int main void        int i       while 1            if  scanf   d    amp i     1       Input  abc                 printf  Invalid input  Try again n              else               break                       printf  Int read   d n   i       return 0      Another common problem is mixing scanf   and fgets    Consider    include  lt stdio h gt   int main void        int age      char name 256       printf  Input your age         scanf   d    amp age      Input 10        printf  Input your full name  firstname lastname         fgets name  sizeof name  stdin      Doesn t read         return 0      The call to fgets   doesn t wait for input because the newline left by the previous scanf   call is read and fgets   terminates input reading when it encounters a newline   There are many other similar problems associated with scanf    That s why it s generally recommended to avoid it   So  what s the alternative  Use fgets   function instead in the following fashion to read a single character    include  lt stdio h gt   int main void        char line 256       char ch       if  fgets line  sizeof line  stdin     NULL            printf  Input error  n            exit 1              ch   line 0       printf  Character read   c n   ch       return 0      One detail to be aware of when using fgets   will read in the newline character if there s enough room in the inut buffer  If it s not desirable then you can remove it   char line 256    if  fgets line  sizeof line  stdin     NULL        printf  Input error  n        exit 1      line strcpsn line    n      0     removes the trailing newline  if present

User · Answer

neither fgets nor getchar works to solve the problem  the only workaround is keeping a space before  c while using scanf scanf    c  ch       will only work  In the follwing fgets also not work    char line 256   char ch  int i   printf  Enter a num       scanf   d   amp i   printf  Enter a char        if  fgets line  sizeof line  stdin     NULL        printf  Input error  n        exit 1      ch   line 0   printf  Character read   c n   ch

User · Answer

Before the scanf put fflush stdin   to clear buffer

User · Answer

The  c conversion specifier won t automatically skip any leading whitespace  so if there s a stray newline in the input stream  from a previous entry  for example  the scanf call will consume it immediately   One way around the problem is to put a blank space before the conversion specifier in the format string   scanf    c    amp c     The blank in the format string tells scanf to skip leading whitespace  and the first non-whitespace character will be read with the  c conversion specifier

[c] How to do scanf for single char in C

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