%

[Arithmetic Operators]

描述

Remainder operation calculates the remainder when one integer is divided by another. It is useful for keeping a variable within a particular range (e.g. the size of an array). The % (percent) symbol is used to carry out remainder operation.

語法

remainder = dividend % divisor;

參數

remainder: variable. Allowed data types: int, float, double.
dividend: variable or constant. Allowed data types: int.
divisor: non zero variable or constant. Allowed data types: int.

範例程式碼

int x = 0;
x = 7 % 5;  // x now contains 2
x = 9 % 5;  // x now contains 4
x = 5 % 5;  // x now contains 0
x = 4 % 5;  // x now contains 4
x = -4 % 5; // x now contains -4
x = 4 % -5; // x now contains 4

/* update one value in an array each time through a loop */

int values[10];
int i = 0;

void setup() {}

void loop() {
  values[i] = analogRead(0);
  i = (i + 1) % 10; // remainder operator rolls over variable
}

Tips

1. The remainder operator does not work on floats.
2. If the first operand is negative, the result is negative (or zero). Therefore, the result of x % 10 will not always be between 0 and 9 if x can be negative.

語法參考主頁面

86Duino 參考的文本是根據 知識共享署名-相同方式分享 3.0 許可證，部分文本是從 Arduino 參考 修改的。 參考中的代碼示例已發佈到公共領域。