split string value in arrays - c

Question

I have to split a string-input value where-ever there is a blankspace and output the result.
eg: input:
I am a noob at C
output:
>>I
>>am
>>a
>>noob
>>at
>>C
Code:
void splitText(){
char str[100];
char sep[] = " \r\n";
char *res; //if i remove this
fgets(str,sizeof str,stdin);
if (fgets(str, sizeof str, stdin) == NULL) {
printf("error");
}
char *p = strchr(str, '\n');
if (p) *p = 0;
res = strtok(str, sep); //and this
printf("%s\n",res); //and change this to str
}
Working code for anyone encountering the same problem:
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
void splitText() {
char str[100];
char sep[] = " \n";
char *res;
fgets(str,sizeof str, stdin);
if ( fgets(str, sizeof str, stdin) == NULL ) {
printf("Error");
break;
}
res = strtok(str, sep);
while(res != NULL){
printf("Splitted String: \"%s\"\n",res);
res = strtok(NULL,sep);
}
}
Thanks to everyone who contributed in helping me with this issue!

Answer 1

The problem with
char str[100] = scanf("%s",str);
is that you are assigning an int to a char array.
scanf() returns the number of items successfully scanned. The actual reading of chars into the array is done by scanf() itself. So you just need to call scanf() separately.
if (scanf("%s",str) != 1) { /* error */}
But scanf() is not the right tool here since you want to read a whole line. scanf() would stop at the first whitespace (after reading non-whitespace chars).
So when you type "I am a noob at C", scanf() will only read the I and ignore the rest.
What you want is to use the fgets() function to read a line:
char str[100];
if (fgets(str, sizeof str, stdin) == NULL) {
/* error */
}
/* rest of the code */
fgets() would read the newline as well if there's space in the buffer. If this is undesirable, then you can remove it:
char *p = strchr(str, '\n');
if (p) *p = 0; //remove the trailing newline.
Note: strtok() is not a thread safe function. POSIX provides strtok_r() as a thread-safe alternative. This is something to be aware of even if it doesn't matter in this specific case.
Here's a self contained example:
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
int main(void) {
char str[100];
char sep[] = " \n";
char *res;
if ( fgets(str, sizeof str, stdin) == NULL ) {
exit(1);
}
res = strtok(str, sep);
while(res != NULL){
printf("Splitted String: \"%s\"\n",res);
res = strtok(NULL,sep);
}
return 0;
}

Answer 2

That is not how scanf() works.
Change the code to
char str[100];
scanf("%s",str);
A little note about scanf()
You should check for return values, like here for scanf().
if (scanf("%s", str) != 1)
{
printf("scanf failed");
exit(0);
}
You should also mention the number of chars to be read by scanf() to avoid buffer overflow.
scanf("%99s", str)
For a char str[100] of size 100, one should give 99 to keep place for the null character \0.