do while
The do...while loop will execute the code block first, and then checking if the condition is true, then it will repeat the loop as long as the condition is true.
The do...while loop works in the same manner as the while loop, with the exception that the condition is tested at the end of the loop, so the do loop will always run at least once.
do {
} while (condition);
condition: a boolean expression that evaluates to
true or
false.
void setup() {
Serial.begin(9600);
Serial.println("====== TEST START ======");
int i = 0;
do {
Serial.print("Inside the DO WHILE loop: i = ");
Serial.println(i);
i++;
} while (i < 5);
Serial.println("====== TEST END ========");
}
void loop() {
}
The result on Serial Monitor:
====== TEST START ======
Inside the DO WHILE loop: i = 0
Inside the DO WHILE loop: i = 1
Inside the DO WHILE loop: i = 2
Inside the DO WHILE loop: i = 3
Inside the DO WHILE loop: i = 4
====== TEST END ========
int x = 0;
do {
delay(50);
x = readSensors();
} while (x < 100);
The while loop checks the condition before executing the block of code; conversely, the do while loop checks the condition after executing the block of code. Therefore, the do while loop will always be executed at least once, even if the condition is false at the beginning.
The do...while and while loop are the same, except for the case in which the condition is false at the beginning.
For example:
void setup() {
Serial.begin(9600);
Serial.println("====== TEST START ======");
int i = 10;
do {
Serial.print("Inside the DO WHILE loop: i = ");
Serial.println(i);
i++;
} while (i < 5);
Serial.println("====== TEST END ========");
}
void loop() {
}
====== TEST START ======
Inside the DO WHILE loop: i = 10
====== TEST END ========
void setup() {
Serial.begin(9600);
Serial.println("====== TEST START ======");
int i = 10;
while (i < 5) {
Serial.print("Inside the DO WHILE loop: i = ");
Serial.println(i);
i++;
}
Serial.println("====== TEST END ========");
}
void loop() {
}
====== TEST START ======
====== TEST END ========
※ NOTES AND WARNINGS:
There are three ways to escape the do while loop:
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