为什么此C代码总是输出笑脸？

Question

#include <stdio.h>
#include <stdlib.h>
//A simple program that asks for the user's name and prints it back out.
int main()
{
    char name[15]; 
    printf("What is your name? ");
    scanf("%c",&name);
    printf("Name: %c",name);
}

Not matter what the input is, a smiley face is always the output. I realize that if I change the %c to a %s, the program would run just fine but what I'm wondering is why, out of all things, a smiley face is the output. Also, if the second %c is replaced with a %s ie

char name[15]; 
printf("What is your name? ");
scanf("%c",&name);
printf("Name: %s",name);

then an @ symbol is printed after the 1st character of the input. For example, if the input is "Sam", then the output would be "S@". Any ideas as to why this happens?

Answer 1

It's undefined behavior, try

scanf("%14s", name);

You pass the wrong parameter to the "%c" specifier which expects a pointer to a single char . Instead you need the "%s" specifier and since name is an array it's automatically a pointer to it's first element so you don't need the & address of operator.