`1)`

#include <stdio.h>
int main() {
    long long a;
    scanf("%lld", &a);
    if (a == 0) printf("So khong");
    else if (a < 0) printf("So nguyen am");
    else printf("So nguyen duong");
    return 0;
}

`2)`

#include <stdio.h>
int main() {
    long long a,b,c,t;
    printf("Nhap a: "); scanf("%lld", &a);
    printf("Nhap b: "); scanf("%lld", &b);
    printf("Nhap c: "); scanf("%lld", &c);
    if (a < b) {
        t = a;
        a = b;
        b = t;
    }
    if (a < c) {
        t = a;
        a = c;
        c = t;
    }
    printf("%lld", a);
}

\begin{array}{c} \color{#db1616}{\texttt{#Khoadang09}} \end{array}
`@`$\texttt{C: }$

*Câu 1 :

#include <stdio.h>
#define int long long
#define zero 0
signed main(){
    int a;
    scanf("%lld",&a);
    if (a==zero)
        printf("So vua nhap la so 0");
    else if (a>zero)
        printf("So vua nhap la so nguyen duong");
    else
        printf("So vua nhap la so nguyen am");
    return 0;
}

*Câu 2 :

#include <stdio.h>
#define int long long
signed main(){
    int a, b, c;
    scanf("%lld%lld%lld",&a,&b,&c);
    int max = a;
    if (max < b)
        max = b;
    if (max < c)
        max = c;
    printf("%lld",max);
}