Literals in C/C++ With Examples

Literals are the Constant values that are assigned to the constant variables. Literals represent fixed values that cannot be modified. Literals contain memory but they do not have references as variables. Generally, both terms, constants, and literals are used interchangeably. 

For example, “const int = 5;“, is a constant expression and the value 5 is referred to as a constant integer literal. There are 4 types of literal in C and five types of literal in C++. 

• Integer literal
• Float literal
• Character literal
• String literal
  

1) Integer Literals

Integer literals are used to represent and store the integer values only. Integer literals are expressed in two types i.e.

A) Prefixes: The Prefix of the integer literal indicates the base in which it is to be read.

For Example:

0x10 = 16

Because 0x prefix represents a HexaDecimal base. So 10 in HexaDecimal is 16 in Decimal. Hence the value 16.

There are basically represented into 4 types:

a. Decimal-literal(base 10): A non-zero decimal digit followed by zero or more decimal digits(0, 1, 2, 3, 4, 5, 6, 7, 8, 9).

Example:

56, 78

b. Octal-literal(base 8): a 0 followed by zero or more octal digits(0, 1, 2, 3, 4, 5, 6, 7).

Example:

045, 076, 06210

c. Hex-literal(base 16): 0x or 0X followed by one or more hexadecimal digits(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, a, A, b, B, c, C, d, D, e, E, f, F).

Example:

0x23A, 0Xb4C, 0xFEA

d. Binary-literal(base 2): 0b or 0B followed by one or more binary digits(0, 1).

Example:

0b101, 0B111

B) Suffixes: The Prefix of the integer literal indicates the type in which it is to be read.

For example:

12345678901234LL 

indicates a long long integer value 12345678901234 because of the suffix LL

These are represented in many ways according to their data types.

• int: No suffix is required because integer constant is by default assigned as an int data type.
• unsigned int: character u or U at the end of an integer constant.
• long int: character l or L at the end of an integer constant.
• unsigned long int: character ul or UL at the end of an integer constant.
• long long int: character ll or LL at the end of an integer constant.
• unsigned long long int: character ull or ULL at the end of an integer constant.

Example:

C

#include <stdio.h>

int main()
{

    // constant integer literal
    const int intVal = 10;

    printf("Integer Literal:%d \n", intVal);
    return 0;
}

C++

#include <iostream>
using namespace std;

int main()
{
    // constant integer literal
    const int intVal = 10;
    cout << "Integer Literal: "
         << intVal << "\n";

    return 0;
}

Output:

Integer Literal:10

2) Floating-Point Literals

These are used to represent and store real numbers. The real number has an integer part, real part, fractional part, and exponential part. The floating-point literals can be stored either in decimal form or exponential form. While representing the floating-point decimals one must keep two things in mind to produce valid literal:

• In the decimal form, one must include the decimal point, exponent part, or both, otherwise, it will lead to an error.
• In the exponential form, one must include the integer part, fractional part, or both, otherwise, it will lead to an error.

A few floating-point literal representations are shown below:

Valid Floating Literals:

10.125
1.215-10L
10.5E-3

Invalid Floating Literals:

123E
1250f
0.e879

Example:

C++

#include <iostream>
using namespace std;

int main()
{
    // Real literal
    const float floatVal = 4.14;

    cout << "Floating-point literal: "
         << floatVal << "\n";
    return 0;
}

C

#include <stdio.h>

int main()
{
    // constant float literal
    const float floatVal = 4.14;

    printf("Floating point literal: %.2f\n",
        floatVal);
    return 0;
}

Output:

Floating point literal: 4.14

3) Character Literal

This refers to the literal that is used to store a single character within a single quote. To store multiple characters, one needs to use a character array. Storing more than one character within a single quote will throw a warning and display just the last character of the literal. It gives rise to the following two representations:

A. char type: This is used to store normal character literal or narrow-character literals. This is supported by both C and C++.

Example:

// For C
char chr = 'G';

// For C++
char chr = 'G';

B. wchar_t type: This literal is supported only in C++ and not in C. If the character is followed by L, then the literal needs to be stored in wchar_t. This represents a wide-character literal.

Example:

// Not Supported For C

// For C++
wchar_t chr = L'G';

Example:

C

#include <stdio.h>

int main()
{
    // constant char literal
    const char charVal = 'A';

    printf("Character Literal: %c\n",
        charVal);
    return 0;
}

C++

#include <iostream>
using namespace std;

int main()
{
    // constant char literal
    const char charVal = 'A';

    // wide char literal
    const wchar_t charVal1 = L'A';

    cout << "Character Literal: "
         << charVal << "\n";
    cout << "Wide_Character Literal: "
         << charVal1 << "\n";

    return 0;
}

// output
// Character Literal: A
// Wide_Character Literal: 65

Output:

Character Literal: A

Escape Sequences: There are various special characters that one can use to perform various operations.

4) String Literals

String literals are similar to that character literals, except that they can store multiple characters and uses a double quote to store the same. It can also accommodate the special characters and escape sequences mentioned in the table above. We can break a long line into multiple lines using string literal and can separate them with the help of white spaces.

Example:

// For C
char stringVal[] = "GeeksforGeeks";

// For C++
string stringVal = "GeeksforGeeks"

Example:

C++

#include <iostream>
using namespace std;

int main()
{
    const string str
        = "Welcome\nTo\nGeeks\tFor\tGeeks";
    cout << str;
    return 0;
}

C

#include <stdio.h>

int main()
{
    const char str[]
        = "Welcome\nTo\nGeeks\tFor\tGeeks";
    printf("%s", str);
    return 0;
}

Output:

Welcome
To
Geeks    For    Geeks

5) Boolean Literals

This literal is provided only in C++ and not in C. They are used to represent the boolean datatypes. These can carry two values:

• true: To represent True value. This must not be considered equal to int 1.
• false: To represent a False value. This must not be considered equal to int 0.

Example:

C++

// C++ program to show Boolean literals

#include <iostream>
using namespace std;

int main()
{
    const bool isTrue = true;
    const bool isFalse = false;

    cout << "isTrue? "
        << isTrue << "\n";
    cout << "isFalse? "
        << isFalse << "\n";

    return 0;
}

Output:

isTrue? 1
isFalse? 0