C Program to Display Characters from A to Z Using Loop

In this example, you will learn to print all the letters of the English alphabet.
English alphabets

To understand this example, you should have the knowledge of the following C programming topics:

Program to Print English Alphabets

#include <stdio.h>
int main() {
    char c;
    for (c = 'A'; c <= 'Z'; ++c)
        printf("%c ", c);
    return 0;
}

Output

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

In this program, the for loop is used to display the English alphabet in uppercase.

Here's a little modification of the above program. The program displays the English alphabet in either uppercase or lowercase depending upon the input given by the user.


Print Lowercase/Uppercase alphabets

#include <stdio.h>
int main() {
    char c;
    printf("Enter u to display uppercase alphabets.\n");
    printf("Enter l to display lowercase alphabets. \n");
    scanf("%c", &c);

    if (c == 'U' || c == 'u') {
        for (c = 'A'; c <= 'Z'; ++c)
            printf("%c ", c);
    } else if (c == 'L' || c == 'l') {
        for (c = 'a'; c <= 'z'; ++c)
            printf("%c ", c);
    } else {
        printf("Error! You entered an invalid character.");
    }

    return 0;
}

Output

Enter u to display uppercase alphabets. 
Enter l to display lowercase alphabets. l
a b c d e f g h i j k l m n o p q r s t u v w x y z