小弟是C的初学者，哪位好心的哥哥姐姐能帮我解决下面两个问题，万分感谢！！！！

1.Write a C program that reads in two integers into two variables using scanf. The program should switch the two integers without using a third variable. The program should output the new values of the integers.

2.Write a C program that reads in three integers using scanf, and prints out the maximum of the three integers.

1，

#include <stdio.h>

int main (void) {

        int a,b;
        void exchange(int *a,int *b);
        scanf("%i%i",&a,&b);
        printf("a=%i b=%i\n",a,b);
        exchange(&a,&b);
        printf("a=%i b=%i\n",a,b);

        return 0;
}
void exchange(int *a,int *b) {
        int temp;
        temp=*a;
        *a=*b;
        *b=temp;
}
root@~ #./a1
12 13
a=12 b=13
a=13 b=12
root@~ #

2，

#include <stdio.h>
int main (void) {
        int x,y,z,max;
        printf ("Please three digit:\n");
        scanf ("%i%i%i",&x,&y,&z);
        printf ("Max digit is:%i\n",(x>y?(x>z?x:z):(y>z?y:z)));
        return 0;
}

1.
int a,b;
scanf("%d%d",&a,&b);
a=a+b;
b=a-b;
a=a-b;
printf("%d,%d",a,b);

2.int a,b,c;
scanf("%d%d%d",&a,&b,&c);
int max=a>b?a:b;
max=max>c?max:c;
printf("%d",max);

小弟谢谢二位啦！！