HackerRank C- Pointers in C

You have to complete the function void update(int *a,int *b), which reads two integers as argument, and sets with the sum of them, and b with the absolute difference of them.

#include <stdio.h>

void update(int *a,int *b) {
      *a=*a+(*b);
      *b=(*a)-(*b)-(*b);
      if(*b<0)
      {
          
          *b=*b*(-1);
      }
      
}

int main() {
    int a, b;
    int *pa = &a, *pb = &b;
    
    scanf("%d %d", &a, &b);
    update(pa, pb);
    printf("%d\n%d", a, b);

    return 0;
}