character as integers in C programming language

Question

Can character be classified as an integer in C language.

I am talking in context of a lexical analyzer.I am building a scanner using C language.

possible duplicate of [What is an unsigned char?](http://stackoverflow.com/questions/75191/what-is-an-unsigned-char) — Math, Sep 18 '13 at 12:05

score 1 · Answer 1 · answered Sep 18 '13 at 11:12

1

You can simply do:

const char str[] = "Hello world";
char c = 'H';

// And use any of these:
int chr = 'H'; // chr = 0x48
chr = c; // chr = 0x48
chr = str[0]; // chr = 0x48

And you'll always end up having 0x48 (72) in chr.

answered Sep 18 '13 at 11:12

Vyktor

20,559
6
64
96

Not always. Not all C implementations use ASCII. – Eric Postpischil Sep 18 '13 at 12:44
@EricPostpischil can you be more specific? I'm curious where it'll get another result. – Vyktor Sep 18 '13 at 17:05
EBCDIC is not dead yet, and a compiler for an embedded system could make up its own character encoding. – Eric Postpischil Sep 18 '13 at 17:09
@EricPostpischil oh, that charset table (characters not grouped together but having spaces between `i` and `j`, `r` and `s`) looks terrible to me (but I assume there's historical reason for it). So what formulation do you suggest? Perhaps "*at least on linux and windows platforms*"? – Vyktor Sep 19 '13 at 06:29
The EBCDIC character codes are influenced by the available positions for holes on [Hollerith punched cards](http://en.wikipedia.org/wiki/Punched_card). The characters step through punches in rows 1-9, then change one of the other rows, then step again. Simply write “The value of `'H'` is the numeric code for the character “H” in the execution character set, which is 72 in ASCII (the most commonly used character set).” You cannot qualify this by Linux or Windows platform, because anybody may write a C implementation for those platforms that does not use ASCII. – Eric Postpischil Sep 19 '13 at 12:26

Math · Answer 2 · 2013-09-18T13:36:42.667

Perhaps you want to ask if char can be classified as numbers. If so, yes they can, as char variables stores the value of a char as a number.

Say:

char c = 120; //legal

The range of the numbers you can store in a char depends on the compiler. Most commonly, char variables stores values of a range from -128 to 127, total 256 possibilities.

As per Variables. Data Types. - C++ Documentation

You can also work with unsigned chars, that goes from 0 to 255.

Please realize that if you store a number out of this range you will lose precision. Say:

char c = 300;
int i = c;
std::cout << i;   //prints 44
system("pause");
return 0;

krouis · Answer 3 · 2013-09-18T12:48:03.503

In "The C Programming Language" (second edition) it is specifically mentioned that there is no distinction between char and int types as far as character manipulation functions of stdio.h are concerned.

The type char is specifically meant for storing (such) character data, but any integer type can be used

This is an example adapted from the book and illustrating this:

#include <stdio.h>
/* copy input to output */
int
main(void)
{
  int c;
  while ((c = getchar()) != EOF)
    putchar(c);
}

score 0 · Answer 4 · answered Sep 18 '13 at 11:24

0

Of course, charactor can be implicitly converted to an integer.

char a = 'c';
int b = a;

answered Sep 18 '13 at 11:24

styshoo

111
4

score 0 · Answer 5 · answered Sep 18 '13 at 11:26

0

Using TypeCasting:

char c = 'a';
int x = (int) c;
printf("%d\n", c);

OR

char c = 'a';
printf("%d\n", c);

Both will give you 97

answered Sep 18 '13 at 11:26

Vishwadeep Singh

1,043
1
13
38

1

No need to cast `c`. The value of `c` is simply the ASCII-value of `a`, which is a digit. – pzaenger Sep 18 '13 at 11:29
yup.. thats why i provided OR statement.. :) – Vishwadeep Singh Sep 18 '13 at 11:32

score 0 · Answer 6 · answered Sep 18 '13 at 11:46

0

Characters are represented as integers. One common pitfall when analysibng input is shown below:

char c; // (!!) should be of type int to hold EOF

while((c = getchar()) != EOF) {
  // ...
}

answered Sep 18 '13 at 11:46

jev

2,023
1
17
26

score 0 · Answer 7 · answered Sep 18 '13 at 13:10

char is an integer type like int with a reduced range.

You can add, multiply, shift, print, scan as you would with int, short, long or long long. char has a smaller range than the others. Much code involving char and short silently promote to int, so care is needed.

char c;
int i;

c = -2; // OK
i = -2; // OK

// sizeof(c) == 1
// sizeof(i) >= 2  (often 4, sometimes 8)

scanf("%hhd", &c);
scanf("%d", &i);

printf("%hhd", c);
printf("%d", i);

On exotic machines where a byte is > 9 bits, additional issues apply.

character as integers in C programming language

7 Answers7