# Input and Output – HackerRank Solution ## Objective :

In this challenge, we’re practicing reading input from stdin and printing output to stdout.

## Question :

In C++, you can read a single whitespace-separated token of input using cin, and print output to stdout using cout. For example, let’s say we declare the following variables:

``````string s;
int n;``````

and we want to use cin to read the input “High 5” from stdin. We can do this with the following code:

``cin >> s >> n;``

The above code reads the first word (“High”) from stdin and saves it as string  `s`, then reads the second word (“`5`“) from stdin and saves it as integer `n` . If we want to print these values to stdout, we write the following code:

``cout << s << " " << n << endl;``

The above code prints the contents of string `s`, which is the word “High”. Then it prints a single space (`" "`), followed by the contents of integer `n`. Because we also want to ensure that nothing else is printed on this line, we end our line of output with a newline via endl. This results in the following output:

``High 5``

Read `3` numbers from stdin and print their sum to stdout.

Note: If you plan on completing this challenge in C instead of C++, you’ll need to use format specifiers with printf and scanf.

### Input Format :

A single line containing `3` space-separated integers: `a``b`, and `c`.

### Constraints :

• `1 <= a, b, c <= 1000`

### Output Format :

Print the sum of the three numbers on a single line.

### Sample Input :

``1 2 7``

### Sample Output :

``10``

### Explanation :

The sum of the three numbers is `1 + 2 + 7 = 10`.

## Solution :

``````#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;

int main() {
int sum, a;
while(cin >> a) {
sum += a;
}
cout << sum;
return 0;
}``````

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