C++ Program to Convert Uppercase to Lowercase Characters

In this C++ program, we will convert a Uppercase character to lowercase character. We will ask user to enter an uppercase character and then convert it to lowercase character. To convert an uppercase character to lowercase, we will add 32 to the ASCII value of uppercase to get corresponding lowercase character.

Points to Remember
    The difference between ASCII value of Lowercase alphabet and it Uppercase equivalent alphabet is 32.
For Example :
ASCII value of 'B' is 66
ASCII value of 'b' is 98
'b' - 'B' = 98 - 66 = 32

C++ Program to Convert Uppercase alphabet to Lowercase

//C++ Program to convert uppercase to lowercase alphabet
#include <iostream>
using namespace std;

int main() {
    char c;
 
    cout << "Enter an uppercase alphabet\n";
    cin >> c;
 
    if(c >= 'A' && c <= 'Z'){
        // Add 32 to uppercase character to 
        // convert it to lowercase
        c += 32;
        cout << "Lowercase Alphabet : " << c;
    } else {
        cout << "Not an uppercase Alphabet";
    }

    return 0;
}
Output
Enter an uppercase alphabet
F
Lowercase Alphabet : f
Enter an uppercase alphabet
g
Not an uppercase Alphabet

In above program, we first take a character as input from user using cin and store it in variable c. Then using a if-else statement, we check whether c is uppercase character or not. If c is uppercase alphabet then we add 32 from c to get it's lowercase equivalent character.


C++ Program to Convert Uppercase String to Lowercase String

//C++ Program to convert lowercase string to uppercase
#include <iostream>
#include <cstring>
using namespace std;

int main(){
    char input[100];
    int i, j;
    
    cout << "Enter a string \n";
    cin.getline(input, 500);
    
    for(i = 0; input[i] != '\0'; i++){
        if(input[i] >= 'a' && input[i] <= 'z'){
            // If current character is a lowercase alphabet, 
     // then subtract 32 to convert it to lowercase
            input[i]-= 32;
        }
    }
    
    cout << "String without lower alphabets\n" << input;
     
    return 0;
}
Output
Enter a string 
TecHcRAshCOurSE
String without lower alphabets
TECHCRASHCOURSE

In above program, we first take a string input from user using cin and store it in a character array "input". Using a for loop, we traverse input string from first character to last character and check whether current character is uppercase or not. If current character is uppercase alphabet then we add 32 to get it's lowercase equivalent character. Finally, we print modified string in screen.