Sample task and solution in c++ : String of Hackerrank

 C++ provides a nice alternative data type to manipulate strings, and the data type is conveniently called string. Some of its widely used features are the following:

• Declaration:

  string a = "abc";
  

• Size:

  int len = a.size();
  

• Concatenate two strings:

  string a = "abc";
  string b = "def";
  string c = a + b; // c = "abcdef".
  

• Accessing  element:

  string s = "abc";
  char   c0 = s[0];   // c0 = 'a'
  char   c1 = s[1];   // c1 = 'b'
  char   c2 = s[2];   // c2 = 'c'
  
  s[0] = 'z';         // s = "zbc"
  

P.S.: We will use cin/cout to read/write a string.

Input Format

You are given two strings,  and , separated by a new line. Each string will consist of lower case Latin characters ('a'-'z').

Output Format

In the first line print two space-separated integers, representing the length of  and  respectively.
In the second line print the string produced by concatenating  and  ().
In the third line print two strings separated by a space,  and .  and  are the same as  and , respectively, except that their first characters are swapped.

Sample Input

abcd
ef

Sample Output

4 2
abcdef
ebcd af

Explanation

•  "abcd"
•  "ef"
•  "abcdef"
•  "ebcd"
•  "af"

My Solution

#include <iostream>

#include <string>

using namespace std;

int main() {

    // Complete the program

   

    string a, b;

    //char *ar, *br;

    char at, bt;

    cin >> a >> b;

    at = b[0];

    bt = a[0];

     

    cout <<a.length() <<" "<< b.length() << endl;

    cout << a + b<<endl;

    a[0]=at;

    b[0]=bt;

   

    cout << a << " " << b;

    return 0;

}

Source : HackerRank