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In this tutorial, we will be learning how to write a C program to check whether a given character is uppercase or lowercase using if-else. Also, We will see examples and algorithms for a better understanding of the problem.

Problem Statement

Write a C program that checks whether a given character is uppercase or lowercase. Here Program will take a character as input. If the Given character is in the uppercase output should printed as “The character is uppercase”. And if the Given character is in lowercase, the output should be printed as “The character is lowercase”.

Examples

Enter a character: A
Output: The character A is uppercase.

Enter a character: b
Output: The character b is lowercase.

Enter a character: 7
Output: Input is invalid

In the below program we are using if else statement of the C programming

Algorithm

1. Start the program.
2. Declare a variable character of type char to store the input character.
3. Prompt the user to enter a character by printing the message “Enter a character: “.
4. Read the input character from the user and store it in the character variable using scanf().
5. Use an if-else statement to check the case of the input character:
   • If character is between ‘A’ and ‘Z’, print the message “The character [character] is uppercase.”
   • If character is between ‘a’ and ‘z’, print the message “The character [character] is lowercase.”
   • Otherwise, print the message “The input is invalid”
6. End the program.

Program to check whether a given character is uppercase or lowercase

#include <stdio.h>
int main() {
    char character;
    printf("Enter a character: ");
    scanf(" %c", &character);
    if (character >= 'A' && character <= 'Z') {
        printf("The character %c is uppercase.\n", character);
    }
    else if (character >= 'a' && character <= 'z') {
        printf("The character %c is lowercase.\n", character);
    }
    else {
        printf("The input  %c is invalid.\n", character);
    }
    return 0;
}

Output 1

Enter a character: h
The character h is lowercase

Output 2

Enter a character: A
The character A is uppercase

Program Explanation

• The program starts by including the necessary header file stdio.h.
• The main() function is defined.
• Inside the main() function, a variable character of type char is declared to store the input character.
• The program prompts the user to enter a character by printing the message “Enter a character: “.
• The scanf() function is used to read a character from the user, and the input is stored in the character variable using the %c format specifier. A space is added before %c in scanf to consume any leading whitespace or newline characters from the previous input.
• An if-else statement is used to check the case of the input character:
  • The condition character >= 'A' && character <= 'Z' checks if the character is uppercase.
  • If the character is uppercase, it prints the message “The character [character] is uppercase.” The %c format specifier is used in printf() to print the character.
  • The condition character >= 'a' && character <= 'z' checks if the character is lowercase.
  • If the character is lowercase, it prints the message “The character [character] is lowercase.”
  • If the character is neither uppercase nor lowercase, it prints the message “The character [character] is neither uppercase nor lowercase.”
• The return 0 statement ends the program.

Conclusion

This C program allows the user to enter a character and determines whether it is uppercase or lowercase using if-else statements. It covers all possible cases and provides the appropriate output based on the input character.