Clear input buffer after fgets () in C

Question

#include <stdio.h>
int main()
{
  char name[10];
  for(int i=0;i<=10;i++)
  {
    printf("Who are you? ");
    if(fgets(name,10,stdin)!=NULL)
    printf("Glad to meet you, %s.\n",name);
  }
  return(0);
}

When I entered something more than 10 characters, the loop skips.

Who are you? aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
Glad to meet you, aaaaaaaaa.
Who are you? Glad to meet you, aaaaaaaaa.
Who are you? Glad to meet you, aaaaaaaaa.
Who are you? Glad to meet you, aaaaaaaaa.
Who are you? Glad to meet you, aaaaaaaaa.
Who are you? Glad to meet you, aaaaaaaaa.
Who are you? Glad to meet you, aaaaaaa

I think I want to clear the input buffer from the rest of the characters. What would be the best way to do this ??

Answer 1

check the availability of a new line in name.

#include <stdio.h>
#include <string.h>

int main(void){
    char name[10];

    for(int i=0;i<=10;i++){
        printf("Who are you? ");
        if(fgets(name,10,stdin)){
            char *p;
            if(p=strchr(name, '\n')){//check exist newline
                *p = 0;
            } else {
                scanf("%*[^\n]");scanf("%*c");//clear upto newline
            }
            printf("Glad to meet you, %s.\n", name);
        }
    }
    return(0);//Parentheses is not necessary
}

Answer 2

Check if the fgets()value is received '\n'. If not '\n', some characters in the current line have not been read. You can simply ignore them.

    printf("Who are you? ");
    if (fgets(name, 10, stdin) != NULL) {
        if (!strchr(name, '\n')) {
            // consume rest of chars up to '\n'
            int ch;
            while (((ch = getchar()) != EOF) && (ch != '\n')) /* void */;
            if (ch == EOF) /* input error */;
            printf("Glad to meet you, %s.\n", name);
        } else {
            printf("Glad to meet you, %s.", name); // name includes ENTER
        }
    }

Answer 3

fgets ( ):

C str , (num-1) , , .

Thus, your input (which exceeds the buffer) is read in blocks of 9 characters (+1 char numbering completion).

You need to call fgetsseveral times until the last character you read becomes a newline character (\ n).

Answer 4

You need to find \nusing something like the following:

/* flush unread input buffer */
while( ! strchr( name, '\n' ) )
    if( ! fgets(name,(sizeof name),stdin) )
        break;

Note: not sure if you think this error or function, but short names will include the final one \n. This leads to something like:

Glad to meet you SSS
.