/in/foo.c:1:19: warning: extra tokens at end of #include directive
    1 | #include <stdio.h>#include <stdbool.h>bool isPrime(int n);int main() {    int n;    scanf("%d", &n);    if (isPrime(n)) {        printf("%d is a primer!\n", n);    } else {        printf("%d is not a primer!\n", n);    }        return 0;}bool isPrime(int n) {    if (n <= 1) return false;    if (n == 2) return true;    if (n % 2 == 0) return false;    for (int i = 3; i * i <= n; i += 2) {        if (n % i == 0) return false;    }    return true;}
      |                   ^
/usr/bin/ld: /usr/lib/gcc/x86_64-linux-gnu/12/../../../x86_64-linux-gnu/Scrt1.o: in function `_start':
(.text+0x17): undefined reference to `main'
collect2: error: ld returned 1 exit status