CODEWITHSUNDEEP
c++stringcharint
MS535
MS535

Reputation: 47

subtracting characters of numbers

I am trying to understand what is going on with the code:

cout << '5' - '3';

Is what I am printing an int? Why does it automatically change them to ints when I use the subtraction operator?

Upvotes: 3

Views: 861

Answers (3)

Animesh Kumar Paul
Animesh Kumar Paul

Reputation: 2294

The ASCII value of character is here

Every character in C programming is given an integer value to represent it. That integer value is known as ASCII value of that character. For example: ASCII value of 'a' is 97. For example: If you try to store character 'a' in a char type variable, ASCII value of that character is stored which is 97.

Subtracting between '5' and '3' means subtracting between their ASCII value. So, replace cout << '5' - '3'; with their ASCII value cout << 53 - 51;. Because Every character in C programming is given an integer value to represent it.

There is a subtraction operation between two integer number, so, it prints a integer 2

Upvotes: 0

Cheers and hth. - Alf
Cheers and hth. - Alf

Reputation: 145239

In C++ character literals just denote integer values.

A basic literal like '5' denotes a char integer value, which with almost all extant character encodings is 48 + 5 (because the character 0 is represented as value 48, and the C++ standard guarantees that the digit values are consecutive, although there's no such guarantee for letters).

Then, when you use them in an arithmetic expression, or even just write +'5', the char values are promoted to int. Or less imprecisely, the “usual arithmetic conversions” kick in, and convert up to the nearest type that is int or *higher that can represent all char values. This change of type affects how e.g. cout will present the value.

* Since a char is a single byte by definition, and since int can't be less than one byte, and since in practice all bits of an int are value representation bits, it's at best only in the most pedantic formal that a char can be converted up to a higher type than int. If that possibility exists in the formal, then it's pure language lawyer stuff.

Upvotes: 5

dbush
dbush

Reputation: 223739

What you're doing here is subtracting the value for ASCII character '5' from the value for ASCII character '3'. So '5' - '3' is equivalent to 53 - 51 which results in 2.

Upvotes: 1

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