ASCII Value of a Character: C, C++, Java, Python

A character variable in C, C++, Java, or Python stores an integer, not the letter itself: 'A' stores 65, 'S' stores 83, and 's' stores 115.

Those integers are ASCII values. The ASCII standard (American Standard Code for Information Interchange) maps 128 characters to integers 0 through 127. The table covers control codes, digits, uppercase and lowercase letters, and common punctuation. Knowing the key ranges is a prerequisite for character-classification problems, which appear in AMCAT, CoCubes, and on-campus placement coding rounds.

What Is an ASCII Value?

ASCII is a 7-bit encoding: 128 code points, each an integer from 0 to 127. The entries split into three practical groups:

• Control codes (0–31 and 127): non-printable instructions such as newline (10), horizontal tab (9), and carriage return (13). These appear in input-parsing problems more than in ASCII-value questions.
• Printable ASCII (32–126): the characters you type. Space is 32, digits start at 48, uppercase letters at 65, lowercase at 97.
• Extended ASCII (128–255): vendor-specific extensions not covered by the 7-bit standard. Portable programs avoid relying on these.

The value stored in a char variable is exactly one of these integers. Print that integer and you have the ASCII value. Print the variable as a character and you see the letter.

How Each Language Reads the Integer

C

A char in C holds a small integer (typically 1 byte). Passing it to printf with the %d format specifier prints the integer directly:

char ch = 'S';
printf("%d\n", ch);  /* prints 83 */

No cast is needed. %c prints the character S; %d prints the integer 83. The same variable serves both purposes without any conversion.

C++

C++ inherits char from C. Streams treat char as a character by default, so the explicit (int) cast makes the numeric intent clear:

char ch = 'S';
cout << (int)ch << endl;  // prints 83

Without (int), cout << ch outputs S rather than 83.

Java

Java’s char is a 16-bit unsigned integer storing a UTF-16 code unit. For standard ASCII characters (code points 0–127), the numeric value matches the ASCII table exactly. An explicit cast converts char to int:

char ch = 'S';
int ascii = (int) ch;  // 83
System.out.println(ascii);

Implicit widening also works: int ascii = ch; compiles without a cast in Java.

Python

Python has no char type. A one-character string holds the character. The built-in ord() function returns the Unicode code point, which equals the ASCII value for characters in the 0–127 range:

print(ord('S'))  # 83

The inverse is chr(): chr(83) returns 'S'. This pair appears often in string-transformation and encoding questions.

Programs in C and C++

C Program

#include <stdio.h>

int main() {
    char ch;
    printf("Enter a character: ");
    scanf("%c", &ch);
    printf("ASCII value of '%c' is %d\n", ch, ch);
    return 0;
}

Traced outputs:

• Input S: ASCII value of 'S' is 83
• Input s: ASCII value of 's' is 115
• Input A: ASCII value of 'A' is 65
• Input 0: ASCII value of '0' is 48

The %c and %d format specifiers read the same ch variable; the only difference is how printf interprets the integer it receives.

C++ Program

#include <iostream>
using namespace std;

int main() {
    char ch;
    cout << "Enter a character: ";
    cin >> ch;
    cout << "ASCII value of '" << ch << "' is " << (int)ch << endl;
    return 0;
}

Traced output for input z: ASCII value of 'z' is 122

Programs in Java and Python

Java Program

import java.util.Scanner;

public class AsciiValue {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter a character: ");
        char ch = sc.next().charAt(0);
        int ascii = (int) ch;
        System.out.println("ASCII value of '" + ch + "' is " + ascii);
    }
}

• sc.next() reads one whitespace-delimited token. .charAt(0) picks the first character.
• (int) ch widens the 16-bit char to a 32-bit int.
• Traced output for a: ASCII value of 'a' is 97
• Traced output for Z: ASCII value of 'Z' is 90

Python Program

ch = input("Enter a character: ")
print(f"ASCII value of '{ch}' is {ord(ch)}")

• Traced output for a: ASCII value of 'a' is 97
• Traced output for 9: ASCII value of '9' is 57

ord() raises a TypeError if the string is not exactly one character long. For production code, add a guard: if len(ch) != 1: raise ValueError("single character required"). The chr() inverse is chr(97) which returns 'a'.

Key ASCII Ranges for Placement Tests

Character group	ASCII range	Example values
Control codes	0–31, 127	Newline = 10, Tab = 9
Space	32	First printable character
Digits '0' to '9'	48–57	'0' = 48, '9' = 57
Uppercase 'A' to 'Z'	65–90	'A' = 65, 'Z' = 90
Lowercase 'a' to 'z'	97–122	'a' = 97, 'z' = 122

The offset between corresponding uppercase and lowercase letters is exactly 32. 'a' (97) minus 'A' (65) = 32. This constant holds for all 26 letter pairs and drives the arithmetic case-conversion technique in the next section.

Interview Variants and Edge Cases

These three variants appear in AMCAT and on-campus placement coding rounds alongside programs like the sum of digits and replacing zeros with ones.

Print All Printable ASCII Characters in a Range

#include <stdio.h>

int main() {
    int i;
    for (i = 32; i <= 126; i++) {
        printf("%d : %c\n", i, i);
    }
    return 0;
}

In Python:

for i in range(32, 127):
    print(i, chr(i))

Both loops print each integer from 32 to 126 alongside its character. The upper bound is 126, not 127, because character 127 is the non-printable DEL control code.

Case Conversion Without Library Functions

Subtract 32 to convert lowercase to uppercase; add 32 to go the other direction. This works for all 26 letter pairs and uses no library calls:

char ch = 'a';
if (ch >= 'a' && ch <= 'z') {
    char upper = ch - 32;  /* 'A' */
    printf("%c\n", upper);
}

In Python: chr(ord('a') - 32) returns 'A'. The space complexity of this operation is O(1); it holds a single integer at any point.

Check Whether a Character Is a Digit, Letter, or Special Symbol

Three range checks cover all categories:

• Is a digit: ASCII value is in 48–57 (i.e., ch >= '0' && ch <= '9' in C/C++/Java)
• Is uppercase: ASCII value is in 65–90
• Is lowercase: ASCII value is in 97–122
• Is a special symbol: none of the three conditions above are true

In Python, ch.isdigit(), ch.isupper(), and ch.islower() use these same bounds internally. The explicit ASCII check appears in C placement questions where ctype.h is excluded from test constraints.

The ord() and chr() functions make it straightforward to test these conditions interactively. TinkerLLM provides a browser-based Python sandbox at ₹499 where you can inspect ASCII values and try the case-conversion arithmetic without installing a compiler. The ord()-plus-arithmetic pattern used for case conversion above extends directly to Caesar cipher and ROT13 challenges that appear in later placement rounds.