HackerRank Pointers in C Solution

Objective

In this challenge, you will learn to implement the basic functionalities of pointers in C. A pointer in C is a way to share a memory address among different contexts (primarily functions). They are primarily used whenever a function needs to modify the content of a variable that it does not own.

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 various functions. For example, int* p = &val will assign the memory address of val to pointer p. To access the content of the memory to which the pointer points, prepend it with a *. For example, *p will return the value reflected by val and any modification to it will be reflected at the source (val).

void increment(int *v) {

(*v)++:

int main() {

int a:

scanf("%d", &a);

increment(&a);

printf("%d", a);

return 0;

}

Task

Complete the function void update (int *a, int *b). It receives two integer pointers, int" a and int* b. Set the value of a to their sum, and b to their absolute difference. There is no return value, and no return statement is needed.

• a' = a+b
• b' = a-b

Input Format

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

Output Format

Modify the two values in place and the code stub main() will print their values.

Note: Input/ouput will be automatically handled. You only have to complete the function described in the 'task' section.

Sample Input

4 

5

Sample Output

9

1

Explanation

a=4+5=9

b=4-5=1

HackerRank Pointers in C Solution (Sample-1)

#include <stdio.h>

void update(int *a,int *b) {
    // Complete this function   
    int c,d;
    c = *a + *b;
    
    if(*a >= *b)
        d = *a-*b;
    else
        d = *b-*a;
    
    *a = c;
    *b = d;
}

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;
}

HackerRank Pointers in C Solution (Sample-2)

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

void update(int *x, int *y){

	int a = *x+*y;
	int b = abs(*x-*y);
	*x = a;
	*y = b;
}
int main(){
	 int a,b;

	 scanf("%d%d", &a,&b);

	 int *ptra= &a;
	 int *ptrb= &b;	 
	 update(ptra,ptrb);

	 printf("%d\n%d\n",*ptra,*ptrb);

	 return 0;

}

HackerRank Pointers in C Solution (Sample-3)

#include <stdio.h>

void update(int *a,int *b) {
	// Complete this function    
	int sum = *a + *b;
	int abs_val = *a - *b;

	if(abs_val < 0) {
		abs_val *= -1;
	}

	*a = sum;
	*b = abs_val;
}

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;
}