How to Take whitespace in Input in C

Question

I wanted to take character array from console and it also include white spaces, the only method i know in C is scanf, but it miss stop taking input once it hit with white space. What i should do?

Here is what i am doing.

char address[100];

scanf("%s", address);

Answer 1

Try using fgets(). It will read a complete line from a stream of your choice (stdin, I guess you're looking for). An example for your case:

char address[100];

fgets(address, 100, stdin);

fgets() will read at most the number of characters passed in the second argument (minus one). No buffer overflow, and you'll get the whole line up to and including a newline character (or up to EOF). Note that since a maximum number of characters to read is one of the parameters, it is possible that you will get a partial line. Check to see if the last character in the returned string is '\n', and you'll know you got a complete line. EOF detection is pretty straightforward too; a NULL return value and a check to errno should help you out.

Thanks to Chris (below), for the point about partial lines.

Answer 2

See fgets()

fgets() reads in at most one less than size characters from stream and stores them into the buffer pointed to by s. Reading stops after an EOF or a newline. If a newline is read, it is stored into the buffer. A '\0' is stored after the last character in the buffer.

char *fgets(char *s, int size, FILE *stream);

Further detail available in many SO questions, for example input-string-through-scanf.

(Due to popular demand, refrence to gets() was removed)

Answer 3

You can try something like this:

char str[100];
scanf("%99[0-9a-zA-Z ]s", str);
printf("%s\n", str);

Answer 4

There are ways to do it with scanf(), but in my humble opinion they get ugly fast. The common pattern (that surprisingly hasn't been mentioned yet) is to read the string in with fgets() and then use sscanf() to process it. sscanf() works like scanf(), only instead of processing the standard input stream, it processes a string that you pass to it (the same way printf() and sprintf() are related). The basics:

char s[100], str[100];
int i, x;
fgets(s, 100, stdin);
if(sscanf(s, "%d %x %s", &i, &x, str) != 3)
  {
    // our three variables weren't all set - probably an invalid string
    // either handle the error or set default values here.
  }

Answer 5

Personally I would use fgets, but that has been already pointed out here. One way of doiung it using scanf would be

scanf("%[^\n]", address);

This takes in all chars until a '\n' is found.

Answer 6

I have the same problem. If i use scanf somewhere in my code before the line fgets(address,100,stdin) the program will end and will not accept the address input