#include <stdio.h>

void checkeligibility(int age){
    if (age < 1||age>100)
    {
        printf("Invalid input\n");
    }else if (age >=18)
    {
        printf("Eligible\n");
    }else
    {
        printf("Not eligible\n");
    }
}
int main(){
    int age;
    printf("enter age: ");
    scanf("%d", &age);
    checkeligibility(a
}