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, , prepend it with sign. For example, &val returns the memory address of .
This memory address is assigned to a pointer and can be shared among various functions. For example, will assign the memory address of to pointer . 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 and any modification to it will be reflected at the source ().
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 to their sum, and to their absolute difference. There is no return value, and no return statement is needed.
Input Format
The input will contain two integers, and , 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
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;
}