C++ Vector Exercises: Capitalize the first character of each vector element

Last update on April 12 2025 13:01:25 (UTC/GMT +8 hours)

4. Capitalize First Letter of Each Vector String

Write a C++ program to capitalize the first character of each element of a given string vector. Return the new vector.

Sample Data:
({"red", "green", "black", "white", "Pink"}) ->
("Red", "Green", "Black", "White", "Pink"})

Sample Solution-1:

C++ Code:

#include <algorithm>    // Including the Algorithm Library for certain functions like sort
#include <iostream>     // Including the Input/Output Stream Library
#include <vector>       // Including the Vector Library for using vectors

using namespace std;    // Using the Standard Namespace

// Function to modify the vector of strings by capitalizing the first character of each word and converting the rest to lowercase
std::vector<std::string> test(std::vector<std::string> colors) {
  for(int i = 0; i < colors.size(); i++) { // Looping through each string in the vector
    colors[0][0] = toupper(colors[0][0]); // Capitalizing the first character of the first string in the vector

    // Capitalizing the first character of each string in the vector and converting the rest to lowercase
    colors[i][0] = toupper(colors[i][0]); // Capitalizing the first character of the current string
    for(int l = 1; l < colors[i].size(); l++) { // Looping through the characters of the current string (except the first character)
      colors[i][l] = tolower(colors[i][l]); // Converting characters to lowercase
    }
  }
  return colors; // Returning the modified vector of strings
}

// Main function
int main() {
  vector<string> colors = {"red", "green", "black", "white", "Pink"}; // Initializing a vector of strings

  cout << "Original Vector elements:\n";
  for (string c : colors)
    cout << c << " "; // Printing the original elements of the vector

  vector<string> result = test(colors); // Calling the test function to modify the strings in the vector
  cout << "\n\nCapitalize the first character of each vector element:\n";
  for (string c : result)
    cout << c << " "; // Printing the modified elements of the vector
}

Sample Output:

Original Vector elements:
red green black white Pink 

Capitalize the first character of each vector element:
Red Green Black White Pink

Flowchart:

Sample Solution-2:

C++ Code:

#include <algorithm>    // Including the Algorithm Library for certain functions like transform
#include <iostream>     // Including the Input/Output Stream Library
#include <vector>       // Including the Vector Library for using vectors

using namespace std;    // Using the Standard Namespace

// Function to modify the vector of strings by capitalizing the first character of each word and converting the rest to lowercase
std::vector<std::string> test(std::vector<std::string> colors) {
  for (std::string &cl : colors) { // Looping through each string in the vector by reference
    std::transform(cl.begin(), cl.end(), cl.begin(), ::tolower); // Converting all characters in the string to lowercase
    cl[0] = std::toupper(cl[0]); // Capitalizing the first character of the string
  }
  return colors; // Returning the modified vector of strings
}

// Main function
int main() {
  vector<string> colors = {"red", "green", "black", "white", "Pink"}; // Initializing a vector of strings

  cout << "Original Vector elements:\n";
  for (string c : colors)
    cout << c << " "; // Printing the original elements of the vector

  vector<string> result = test(colors); // Calling the test function to modify the strings in the vector
  cout << "\n\nCapitalize the first character of each vector element:\n";
  for (string c : result)
    cout << c << " "; // Printing the modified elements of the vector
}

Sample Output:

Original Vector elements:
red green black white Pink 

Capitalize the first character of each vector element:
Red Green Black White Pink

Flowchart:

For more Practice: Solve these Related Problems:

Write a C++ program that reads a vector of strings and returns a new vector with each string’s first character capitalized using ASCII conversion.
Write a C++ program to iterate over a vector of words and convert the first letter of each word to uppercase without using library functions.
Write a C++ program that processes a string vector and prints each word with the first letter capitalized and the rest in lowercase.
Write a C++ program to modify a vector of strings in-place so that every word starts with an uppercase letter, handling empty strings gracefully.

C++ Code Editor:

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