C++ Program to Check Alphabet or Not

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Here you will learn and get code on checking whether the given character by user at run-time is an alphabet or not in C++. The program is created in following two ways:

Check alphabet or not using character itself
Check alphabet or not using its ASCII value

Check Alphabet or Not in C++

To check whether the entered character is an alphabet or not in C++ programming, you have to ask from user to enter a character and start checking for alphabet.

This program uses if-else statement to check whether the value of character is greater than or equal to a and less than or equal to z or not. If this condition evaluates to be true, then prints it as alphabet.

Otherwise checks for uppercase. That is, checks whether the value of character is greater than or equal to A (uppercase) and less than or equal to Z (uppercase) or not. If evaluates to be true, then print it as an alphabet. Otherwise, if both the condition evaluates to be false, then print it as not an alphabet.

Following C++ program asks from user to enter a character to check whether it is an alphabet:

#include<iostream>
using namespace std;
int main()
{
    char ch;
    cout<<"Enter a Character: ";
    cin>>ch;
    if((ch>='a' && ch<='z') || (ch>='A' && ch<='Z'))
        cout<<endl<<ch<<" is an Alphabet";
    else
        cout<<endl<<ch<<" isn't an Alphabet";
    cout<<endl;
    return 0;
}

This program was build and run under Code::Blocks IDE. Here is its sample run:

Now supply any input say c and press ENTER key to check whether c is an alphabet or not as shown in the output given below:

Because c is an alphabet, therefore you have seen the above output. Let's try with another input that is a number say 3. Here is the output, you will see for this case:

Because 3 is a number, not an alphabet, therefore the program produced the output as shown in the snapshot given above.

Note - If condition of if statement evaluates to be true, then program flow goes to if's body, otherwise program flow goes to else's body.

Using ASCII Value

Now let's create the same program, i.e., to check whether the given or input character is an alphabet or not using its ASCII value. But before going through this program, if you're not aware about the ASCII value of alphabets, then here is the table for you:

Uppercase Alphabet	ASCII Value
A	65
B	66
C	67
...	...
Z	90
Lowercase Alphabet	ASCII Value
a	97
b	98
c	99
...	...
z	122

Now let's move on and implement it in a program to check alphabet or not. The question is, write a program in C++, to receive a character as input and prints whether it is an alphabet or not. The answer to this question is given below:

To check for alphabet using ASCII value of character. Then if character has ASCII value anything between 65 to 90 or 97 to 122, it is an alphabet. Otherwise, it is not an alphabet.

#include<iostream>
using namespace std;
int main()
{
    char ch;
    int ascii;
    cout<<"Enter a Character: ";
    cin>>ch;
    ascii = ch;
    cout<<endl;
    if(ascii>=65 && ascii<=90)
        cout<<"It is an Uppercase Alphabet";
    else if(ascii>=97 && ascii<=122)
        cout<<"It is a Lowercase Alphabet";
    else
        cout<<"It is not an Alphabet";
    cout<<endl;
    return 0;
}

Here is its sample run with user input as s

Here is another sample run with user input as S

Note - The statement, ascii = ch; initializes the ASCII value of character stored in ch to ascii.

Same Program in Other Languages

C++ Online Test

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