Display Character from A to Z Using Loop

Example #1: Program to Display 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 alphabets in uppercase.

Here's a little modification of the above program to display the English alphabets in either uppercase or lowercase depending upon the input from the user.

Example #2: Program to Display English Alphabets in Uppercase and Lowercase

#include <stdio.h>
int main()
{
    char c;

    printf("Enter u to display alphabets in uppercase. And enter l to display alphabets in lowercase: ");
    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 invalid character.");
    return 0;
}

Output

Enter u to display alphabets in uppercase. And enter l to display alphabets in lowercase: 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