C++ Program to Find Initials of a Name

Given a string name, we have to find the initials of the name 

Examples:

Input: Kamlesh Joshi
Output: K J
We take the first letter of all
words and print in capital letter.

Input: Jude Law
Output: J L

Input: Abhishek Kumar Bisht
Output: A K B

1) Print first character in capital. 
2) Traverse rest of the string and print every character after space in capital letter.

C++

// C++ program to print initials of a name
#include <bits/stdc++.h>
using namespace std;

void printInitials(const string& name)
{
    if (name.length() == 0)
        return;

    // Since toupper() returns int,
    // we do typecasting
    cout << (char)toupper(name[0]);

    // Traverse rest of the string and print the
    // characters after spaces.
    for (int i = 1; i < name.length() - 1; i++)
        if (name[i] == ' ')
            cout << " " << (char)toupper(name[i + 1]);
}

// Driver code
int main()
{
    string name = "Kamlesh Joshi";
    printInitials(name);
    return 0;
}

Output:

K J

Time Complexity: O(n), Here n is the length of the string.
Auxiliary Space: O(1), As constant extra space is used.

Another possible solution is given as follows:

C++

// C++ program to solve the
// above approach
#include <bits/stdc++.h>
using namespace std;

void printInitials(string name)
{
    if (name.length() == 0)
        return;

    // split the string using 'space'
    // and print the first character of
    // every word
    // X is an object of stringstream
    // that references the S string
    stringstream X(name);


    // use while loop to check the
    // getline() function condition
    while (getline(X, name, ' '))
    {
        /* X represents to read the string from
           stringstream, T use for store the
           token string and, ' ' whitespace
           represents to split the string where
           whitespace is found. */

        // Print split string
        cout << (char)toupper(name[0]) << " ";
    }
}

// Driver code
int main()
{
    string name = "Kamlesh Joshi";
    printInitials(name);
    return 0;
}

Output:

K J

Time complexity: O(w), The complexity of this code will be less than O(w) where w is number of words in sentence, which can be little better than number of characters in String. 
We can also use strtok() function in C/C++ to achieve this. 

Auxiliary space: O(1).