C++ Operators

In this tutorial, we will learn C ++Different types of operators. In programming, operators are symbols that perform operations on values or variables.

An operator is a symbol that performs operations on variables and values. For example,+The operator used for addition, while - The operator used for subtraction.

C ++中的运算符可以分为六种类型：

1. 算术运算符

2. Assignment operators

3. Relational operators

4. Logical operators

5. Bitwise operators

6. 其他运算符

1. C ++算术运算符

The operators in can be divided into six types:

a　+　b;

Other operators+Arithmetic operators ++Arithmetic operators are used to perform arithmetic operations on variables and data. For example,

Assuming the value of variable A is 10The value of variable B is 2In this case,

Example1The pre-increment operator increases the integer value

#include <iostream>
using namespace std;
int main() {
　　　　int a, b;
　　　　a =　7;
　　　　b =　2;
　　　　//　The post-decrement operator decreases the integer value
　　　　Print the difference between a and b　+　Print the product of a and b　+　Print a divided by b
　　　　//　A
　　　　Print the difference between a and b　-　Print the product of a and b　-　Print a divided by b
　　　　//　：Arithmetic operators
　　　　Print the difference between a and b　*　Print the product of a and b　*　Print a divided by b
　　　　//　Print the sum of a and b
　　　　Print the difference between a and b　/　Print the product of a and b　/　Print a divided by b
　　　　//　Print the modulus (remainder) of a and b
　　　　cout << "a % b = " << (a % b) << endl;
　　　　return 0;
}

Output result

a　+　b =　9
a　-　b =　5
a　*　b =　14
a　/　b =　3
a % b =　1

Here, the operator+,- and * Calculate addition, subtraction, and multiplication separately, as expected.

/ Division operator

Note the operations in our program (a / b). 　/ The operator is the division operator.

From the above examples, we can see that if one integer is divided by another integer, we will get a quotient. However, if the divisor or dividend is a floating-point number, we will get the result in decimal form.

In C++In,
7/2　=　3
7.0　/　2　=　3.5
7　/　2.0 =　3.5
7.0　/　2.0 =　3.5

％ Modulus operator

The modulus operator % calculates the remainder. When a (9) divided by b(4) with a remainder of1.

Note:The % operator can only be used with integers.

Pre-increment and post-decrement operators

C ++There are also separate increment and decrement operators:++and--.

++Increase the value of the operand1.

-- Decrease the value of the operand1.

For example,

int num =　5;
//　num increases1
++num;

Here, the value of num from the initial value5Increase to6.

Example2：Increment and decrement operators

//　The working of increment and decrement operators
#include <iostream>
using namespace std;
int main() {
　　　　int a =　10, b =　100, result_a, result_b;
　　　　//　Add1and store the result in result_a
　　　　result_a =　++a;
　　　　cout << "result_a = " << result_a << endl;
　　　　//　Subtract1and store the result in result_b
　　　　result_b =　--b;
　　　　cout << "result_b = " << result_b << endl;
　　　　return 0;
}

Output result

result_a =　11
result_b =　99

In the above program, we use++and-Operators can also be used as postfix.

These operators differ slightly when used as prefix and postfix.

2. C ++ Assignment operators

In C ++In C++, the assignment operator is used to assign a value to a variable. For example,

//　to5Assign to a
a =　5;

Here, we assign a value to the variable a5.

Example2: assignment operator

#include <iostream>
using namespace std;
int main() {
　　　　int a, b, temp;
　　　　//　Assign a2
　　　　a =　2;
　　　　//Assign b7
　　　　b =　7;
　　　//　Assign the value of a to temp
　　　temp = a;　　　　//　temp will be　2
　　　cout << "temp = " << temp << endl;
　　　　//　Assign the sum of a and b to a
　　　　a　+= b;　　　　　　　//　a = a　+b
　　　　cout << "a = " << a << endl;
　　　　return 0;
}

Output result

temp =　2
a =　9

3. C ++Relational operators

Relational operators are used to check the relationship between two operands. For example,

//　Check if a is greater than b
a > b;

Here, > is a relational operator. It checks if a is greater than b.

If this relationship istrueThen it returns1;If this relationship isfalseThen it returns0.

Assuming the value of variable A is 5The value of variable B is 11, then:

Example4: relational operators

#include <iostream>
using namespace std;
int main() {
　　　　int a, b;
　　　　a =　3;
　　　　b =　5;
　　　　bool result;
　　　　result = (a == b);　　　//　false
　　　　cout << "3　==　5　The calculation result is " << result << endl;
　　　　result = (a != b);　　//　true
　　　　cout << "3　!=　5　The calculation result is " << result << endl;
　　　　result = a > b;　　　//　false
　　　　cout << "3　>　5　The calculation result is " << result << endl;
　　　　result = a < b;　　　//　true
　　　　cout << "3　<　5　The calculation result is " << result << endl;
　　　　result = a >= b;　　//　false
　　　　cout << "3　>=　5　The calculation result is " << result << endl;
　　　　result = a <= b;　　//　true
　　　　cout << "3　<=　5　The calculation result is " << result << endl;
　　　　return 0;
}

Output result

3　==　5　The calculation result is 0
3　!=　5　The calculation result is　1
3　>　5　The calculation result is 0
3　<　5　The calculation result is　1
3　>=　5　The calculation result is 0
3　<=　5　The calculation result is　1

Note: relational operators are used for decision-making and loops.

4. C ++Logical operators

Logical operators are used to check if an expression istrueorfalse. If the expression istrueThen it returns1;If the expression isfalseThen it returns0.

Assuming the value of variable A is 1If the value of variable B is 0, then:

In C ++In which, logical operators are usually used for decision-making. To better understand logical operators, let's look at the following examples,

Assume,
a =　5
b =　8
Suppose,
(a >　3) && (b >　5) The calculation result is true
(a >　3) && (b <　5) The calculation result is false
(a >　3) || (b >　5) The calculation result is true
(a >　3) || (b <　5) The calculation result is true
(a <　3) || (b <　5) The calculation result is false
!(a ==　3) The calculation result is true
!(a >　3) The calculation result is false

Example5: logical operators

#include <iostream>
using namespace std;
int main() {
　　　　bool result;
　　　　result = (3　!=　5) && (3　<　5);　　　　　//　true
　　　　cout << "(3　!=　5) && (3　<　5) The calculation result is " << result << endl;
　　　　result = (3　==　5) && (3　<　5);　　　　//　false
　　　　cout << "(3　==　5) && (3　<　5) The calculation result is " << result << endl;
　　　　result = (3　==　5) && (3　>　5);　　　　//　false
　　　　cout << "(3　==　5) && (3　>　5) The calculation result is " << result << endl;
　　　　result = (3　!=　5) || (3　<　5);　　　　//　true
　　　　cout << "(3　!=　5) || (3　<　5) The calculation result is " << result << endl;
　　　　result = (3　!=　5) || (3　>　5);　　　　//　true
　　　　cout << "(3　!=　5) || (3　>　5) The calculation result is " << result << endl;
　　　　result = (3　==　5) || (3　>　5);　　　　//　false
　　　　cout << "(3　==　5) || (3　>　5) The calculation result is " << result << endl;
　　　　result = !(5　==　2);　　　　//　true
　　　　cout << "!(5　==　2) The calculation result is " << result << endl;
　　　　result = !(5　==　5);　　　　//　false
　　　　cout << "!(5　==　5) The calculation result is " << result << endl;
　　　　return 0;
}

Output result

(3　!=　5) && (3　<　5) The calculation result is　1
(3　==　5) && (3　<　5) The calculation result is 0
(3　==　5) && (3　>　5) The calculation result is 0
(3　!=　5) || (3　<　5) The calculation result is　1
(3　!=　5) || (3　>　5) The calculation result is　1
(3　==　5) || (3　<　5) The calculation result is 0
!(5　==　2) The calculation result is　1
!(5　==　5) The calculation result is 0

Usage of logical operators in a program

• (3!= 5) && (3 <5) evaluates to1, because both operands(3!= 5) and (3 <5) are1(true).

• (3 == 5) && (3 <5) evaluates to 0 because the operand(3 == 5) evaluates to 0 (false).

• (3 == 5) && (3> 5) evaluate to 0 because both operands(3 == 5) and (3> 5) are both 0 (false).

• (3!= 5) || (3 <5) evaluates to1, because both operands(3!= 5) and (3 <5) are1(true).

• (3!= 5) || (3> 5) evaluates to1, because the operand(3!= 5) is1(true).

• (3 == 5) || (3> 5) evaluate to 0 because both operands(3 == 5) and (3> 5) are both 0 (false).

• !(5 == 2) evaluates to1, because the operand(5 == 2) evaluates to 0 (false).

• !(5 == 5) evaluates to 0 because the operand(5 == 5) is1(true).

5. C ++Bitwise operators

In C ++In which, bitwise operators are used to perform operations on individual bits. They can only be used with char and int data types.

The table below shows C++ supported bit operators. Assume the value of variable A is 60, the value of variable B is 13, then:

For more information, please visitC ++Bitwise operators.

In addition to the operators discussed above, there are also some other operators, such as sizeof, ?, ., & etc., which cannot be neatly divided into one or another type. We will learn more about these operators in future tutorials.

Miscellaneous operators

The following table lists C++ Other important operators supported.

C++ operator precedence in

The precedence of operators determines how terms are combined in an expression. This affects how an expression is calculated. Some operators have higher precedence than others, for example, multiplication and division operators have higher precedence than addition and subtraction operators.

For example x = 7 + 3 * 2Here, x is assigned the value 13, rather than 20, because the operator * with a precedence higher than + higher precedence, so multiplication is calculated first 3*2Then, add 7.

The following table lists operators from highest to lowest precedence, with operators of higher precedence appearing at the top of the table and operators of lower precedence appearing at the bottom. In an expression, operators with higher precedence are calculated first.

Example: Operator precedence

#include <iostream>
using namespace std;
int main() {
　　//　first evaluate17　*　6
　　int num1　=　5　-　17　*　6;
　　//　with num1equivalent expression
　　int num2　=　5　-　(17　*　6);
　　//　force the compiler to evaluate5　-　17value
　　int num3　=5　-　17)　*　6;
　　cout << "num1　=1　<< endl;
　　cout << "num2　=2　<< endl;
　　cout << "num3　=3　<< endl;
　　return 0;
}

num1　=　-97
num2　=　-97
num3　=　-72