CODEWITHSUNDEEP
cscanf
user694733
user694733

Reputation: 16047

sscanf accepts too may spaces

Is there a way to force sscanf to NOT allow extra whitespace.

Following code accepts "N_ 234", even though it should only accept "N_234":

int r;
unsigned b;
r = sscanf("N_ 234", "N_%u", &b); /* Returns 1 */

Tested with IAR compiler.

Upvotes: 4

Views: 171

Answers (2)

Grijesh Chauhan
Grijesh Chauhan

Reputation: 58281

May be my code helpful to you: 

# define SIZE 100
int main(){
    int r;
    unsigned b = 0u;
    char s[SIZE] = {0};
    sscanf("N_234", "%[N_0-9]", s);
    r = sscanf(s,"N_%u",&b);
    printf("%u\n",b);

}

printf("%u\n",b); output correct value if there no space and r is 1, otherwise b = 0 and r is -1 (EOF).

Give it a try!!

EDIT: There is chance of e buffer overrun but can be corrected using dynamic allocation.

Upvotes: 1

4B656E
4B656E

Reputation: 61

Try this:

int r;
unsigned b;
char c[20];
r = sscanf("N_ 234", "N_%[0-9]", c); /* Returns 0 */
r = sscanf("N_-234", "N_%[0-9]", c); /* Returns 0 */
r = sscanf("N_1234", "N_%[0-9]", c); /* Returns 1 */
b = atoi(c);

Upvotes: 2

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