C Operators
Operators
Operators are used to perform operations on variables and values.
In the example below, we use the + operator to add together two values:
Although the + operator is often used to add together two values, like in the example above; it can also be used to add together a variable and a value, or a variable and another variable:
Example
int sum1 = 100 + 50; // 150 (100 + 50)
int sum2 = sum1 + 250; // 400 (150 + 250)
int sum3 = sum2 + sum2; // 800 (400 + 400)
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C divides the operators into the following groups:
- Arithmetic operators
- Assignment operators
- Comparison operators
- Logical operators
- Bitwise operators
Arithmetic Operators
Arithmetic operators are used to perform common mathematical operations.
| Operator | Name | Description | Example | Try it |
|---|---|---|---|---|
| + | Addition | Adds together two values | x + y | Try it ยป |
| - | Subtraction | Subtracts one value from another | x - y | Try it ยป |
| * | Multiplication | Multiplies two values | x * y | Try it ยป |
| / | Division | Divides one value by another | x / y | Try it ยป |
| % | Modulus | Returns the division remainder | x % y | Try it ยป |
| ++ | Increment | Increases the value of a variable by 1 | ++x | Try it ยป |
| -- | Decrement | Decreases the value of a variable by 1 | --x | Try it ยป |
Assignment Operators
Assignment operators are used to assign values to variables.
In the example below, we use the assignment operator (=) to assign the value 10 to a variable called x:
The addition assignment operator (+=) adds a value to a variable:
A list of all assignment operators:
| Operator | Example | Same As | Try it |
|---|---|---|---|
| = | x = 5 | x = 5 | Try it ยป |
| += | x += 3 | x = x + 3 | Try it ยป |
| -= | x -= 3 | x = x - 3 | Try it ยป |
| *= | x *= 3 | x = x * 3 | Try it ยป |
| /= | x /= 3 | x = x / 3 | Try it ยป |
| %= | x %= 3 | x = x % 3 | Try it ยป |
| &= | x &= 3 | x = x & 3 | Try it ยป |
| |= | x |= 3 | x = x | 3 | Try it ยป |
| ^= | x ^= 3 | x = x ^ 3 | Try it ยป |
| >>= | x >>= 3 | x = x >> 3 | Try it ยป |
| <<= | x <<= 3 | x = x << 3 | Try it ยป |
Comparison Operators
Comparison operators are used to compare two values (or variables). This is important in programming, because it helps us to find answers and make decisions.
The return value of a comparison is either 1 or 0, which means true (1) or false (0). These values are known as Boolean values, and you will learn more about them in the Booleans and If..Else chapter.
In the following example, we use the greater than operator (>) to find out if 5 is greater than 3:
Example
int x = 5;
int y = 3;
printf("%d", x > y); // returns 1 (true) because 5 is greater than 3
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A list of all comparison operators:
| Operator | Name | Example | Try it |
|---|---|---|---|
| == | Equal to | x == y | Try it ยป |
| != | Not equal | x != y | Try it ยป |
| > | Greater than | x > y | Try it ยป |
| < | Less than | x < y | Try it ยป |
| >= | Greater than or equal to | x >= y | Try it ยป |
| <= | Less than or equal to | x <= y | Try it ยป |
Logical Operators
You can also test for true or false values with logical operators.
Logical operators are used to determine the logic between variables or values:
| Operator | Name | Description | Example | Try it |
|---|---|---|---|---|
| && | Logical and | Returns true if both statements are true | x < 5 && x < 10 | Try it ยป |
| || | Logical or | Returns true if one of the statements is true | x < 5 || x < 4 | Try it ยป |
| ! | Logical not | Reverse the result, returns false if the result is true | !(x < 5 && x < 10) | Try it ยป |
Sizeof Operator
The memory size (in bytes) of a data type or a variable can be found with the sizeof operator:
Example
int myInt;
float myFloat;
double myDouble;
char myChar;
printf("%lu\n", sizeof(myInt));
printf("%lu\n", sizeof(myFloat));
printf("%lu\n", sizeof(myDouble));
printf("%lu\n", sizeof(myChar));
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Note that we use the %lu format specifer to print the result, instead of %d. It is because the compiler expects the sizeof operator to return a long unsigned int (%lu), instead of int (%d). On some computers it might work with %d, but it is safer to use %lu.
