Pointer in C++ HackerRank solution

A pointer in C++ is used to share a memory address among different contexts (primarily functions). They are used whenever a function needs to modify the content of a variable, but it does not have ownership.

In order to access the memory address of a variable,val , prepend it with  sign &. For example, &val returns the memory address of val.

This memory address is assigned to a pointer and can be shared among functions. For example int*p=val,  assigns the memory address of val to pointer p. To access the content of the memory pointed to, prepend the variable name with a *. For example, *p will return the value stored in val and any modification to it will be performed on val.

void increment(int *v) {
    (*v)++;
}

int main() {
    int a;
    scanf("%d", &a);
    increment(&a);
    printf("%d", a);
    return 0;
} 

Function Description

Complete the update function in the editor below.

update has the following parameters:

• int *a: an integer
• int *b: an integer

Returns

• The function is declared with a void return type, so there is no value to return. Modify the values in memory so that a contains their sum and b contains their absoluted difference.
• a'=a+b
• b'=|a+b|

Input Format

Input will contain two integers, a and b, separated by a newline. 

Sample Input

4
5

Sample output

9
1

Explanation

• a'=4+5=9
• b'=|4-5|=1

Solution

#include <stdio.h>
#include<stdlib.h>

void update(int *a,int *b) 
{  
    int x, y;  
    x = *a + *b ;
    y = *a - *b ;
    *a = x;
    *b = abs(y);

}

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;
}