Programming with the Arduino IDE pt II - Challenges

1. Use nested loops to fill a 3D array.

Answer

Code

void setup() {
  Serial.begin(9600);

  int testArray[3][3][3] = {           //initialize the 3d array
    {
        { 1, 2, 3 },
        { 4, 5, 6 },
        { 7, 8, 9 }
    },
    {
        { 10, 11, 12 },
        { 13, 14, 15 },
        { 16, 17, 18 }
    },
    {
        { 19, 20, 21 },
        { 22, 23, 24 },
        { 25, 26, 27 }
    }
  };

  for ( int i = 0; i < 3; i++)  //"1D" arrays
  {
    for ( int j = 0; j < 3; j++)  //Rows
    { 
      for ( int k = 0; k < 3; k++)  //Columns
      {
        Serial.print(testArray[i][j][k]);  //print columns, rows, and arrays values
        Serial.print(",");                 //print a comma
      }
      Serial.println();                    //new line for new row
    }
    Serial.println();                      //new line for new array
  }

}

void loop() {
}

2. Write a code to produce this result in the serial monitor:

5
44
333
2222
11111

Answer

Code

int x = 5;          //declaring a global value x

void setup() {
  Serial.begin(9600);

  for(int i = 1; i < 6; i++){           //incrementing lines
    for ( int j = 1; j <= i; j++){      //incrementing columns
      Serial.print(x);                  //printing x value
    }
    x--;                                //decrementing x value
    Serial.println();                   //new line
  }
}

void loop() {
}

3. Write a code to produce this result in the serial monitor:

*
**
***
****
*****
****
***
**
*

Answer

Code

void setup() {
  Serial.begin(9600);

  for(int i = 0; i < 5; i++){       //incrementing lines
    for (int j = 0; j < i; j++){    //incrementing columns
      Serial.print('*');            //print "*" when column incrementing
    }
    Serial.println();               //print a new line when line incrementing
  }

  for(int i = 0; i < 5; i++){       //incrementing lines
    for (int j = 5; j > i; j--){    //decrementing columns
      Serial.print('*');            //print "*" when column decrementingcrementing
    }
    Serial.println();               //print a new line when line incrementing
  }  
}

void loop() {
}

4. Using a nested loop for each sentence in a paragraph, count the number of times “the” appears in a given text (saved in a String, for instance).

https://www.arduino.cc/reference/en/language/variables/data-types/string/
https://www.arduino.cc/en/Tutorial/BuiltInExamples/StringSubstring