Data Type Conversion in Arduino

This tutorial covers data type conversion in arduino. Data type conversion or typecasting means converting a value from one data type to other. For example, convert int to float, string to int etc.

Data type covered in this section are int, float, char, char array, string and const char *.

DATA TYPE CONVERSION IN ARDUINO

INT TO OTHER DATA TYPE CONVERSION

This Arduino code will convert data types from int to other, see below

• Convert int to float in Arduino
• Convert int to char in Arduino
• Convert int to char array in Arduino
• Convert int to String in Arduino

// https://pijaeducation.com/data-type-conversion-arduino/

#define delcat 2000
#define delsub 1500
#define delexp 1000

int a = 65;
float d;
char f;
char h[5];
String j;

void setup() {
  Serial.begin(9600);
  Serial.println("Defined Variables are -");
  Serial.println("int a = 65;");
  Serial.println("float d;");
  Serial.println("char f;");
  Serial.println("char h[5];");
  Serial.println("String j;");
  Serial.println();


  /* "INT to OTHER"
    Data type conversion*/
  Serial.println("INT to OTHER Data type conversion");
  delay(delcat);

  d = a;
  Serial.print("integer 65 to float : ");
  delay(delexp);  
  Serial.println(d);

  delay(delsub);
  f = a;
  Serial.print("int 65 to char : ");
  delay(delexp);  
  Serial.println(f);

  delay(delsub);
  itoa(a, h, 10); // int, char[], base
  Serial.print("int 65 to char array : ");
  delay(delexp);  
  Serial.print(h[0]);
  Serial.print(" , ");
  delay(delexp);  
  Serial.println(h[1]);

  delay(delsub);
  j = String(a);
  Serial.print("int 65 to String : ");
  delay(delexp);  
  Serial.println(j);
  Serial.println();

}

void loop() {

}

OUTPUT

FLOAT TO OTHER DATA TYPE CONVERSION

This Arduino code will convert data types from float to other, see below

• Convert float to int in Arduino
• Convert float to String in Arduino

// https://pijaeducation.com/data-type-conversion-arduino/

int iVar;
float fVar = 1.2;
char caVar[10];
String sVar;

void setup() {
  Serial.begin(9600);
  Serial.println("Defined Variables are -");
  Serial.println("int iVar;");
  Serial.println("float fVar = 1.2;");
  Serial.println("char caVar[10];");
  Serial.println("String sVar;");
  Serial.println();


  /* "FLOAT to OTHER" Data type conversion*/
  Serial.println("FLOAT to OTHER Data type conversion");
  Serial.println("");

  iVar = int(fVar);
  Serial.print("float 1.2 to int :");
  Serial.println(iVar);
  Serial.println("");

  Serial.println("float 1.2 to char Array :");
  /* dtostrf(floatVar, minimum_Total_Digits_Including_Decimal_Point, total_Digits_After_Decimal, charArrayVar);
     floatVar → float
     charArrayVar[10] → char
  */
  // at least 4 digits including decimal point, and compulsorily 2 digits after the decimal point
  dtostrf(fVar, 4, 2, caVar);
  Serial.print("dtostrf(fVar, 4, 2, caVar):");
  Serial.println(caVar);
  // at least 5 digits (otherwise include spaces), and compulsorily 2 digits after the decimal point
  dtostrf(fVar, 5, 2, caVar);
  Serial.print("dtostrf(fVar, 5, 2, caVar):");
  Serial.println(caVar);
  // at least 4 digits, and compulsorily 4 digits after the decimal point (otherwise include zeros '0')
  dtostrf(fVar, 4, 4, caVar);
  Serial.print("dtostrf(fVar, 4, 4, caVar):");
  Serial.println(caVar);
  Serial.println("");

  sVar = String(fVar);
  Serial.print("float 1.2 to String :");
  Serial.println(sVar);
  Serial.println();
}


void loop() {
  // put your main code here, to run repeatedly:

}

OUTPUT

CHAR TO OTHER DATA TYPE CONVERSION

This Arduino code will convert data types from char to other, see below

• Convert char to int in Arduino
• Convert char to float in Arduino
• Convert char to String in Arduino

// https://pijaeducation.com/data-type-conversion-arduino/

#define delcat 2000
#define delsub 1500
#define delexp 1000

int b;
float d;
char e = 'a';
String j;

void setup() {
  Serial.begin(9600);
  Serial.println("Defined Variables are -");
  Serial.println("int b;");
  Serial.println("float d;");
  Serial.println("char e = 'a';");
  Serial.println("String j;");
  Serial.println();


  /* "CHAR to OTHER"
    Data type conversion*/
  Serial.println("CHAR to OTHER Data type conversion");
  delay(delcat);

  b = int(e);
  Serial.print("char 'a' to int : ");
  delay(delexp);  
  Serial.println(b);

  delay(delsub);
  d = float(e);
  Serial.print("char 'a' to float : ");
  delay(delexp);  
  Serial.println(d);

  delay(delsub);
  j = String(e);
  Serial.print("char 'a' to String : ");
  delay(delexp);  
  Serial.println(j);
  Serial.println();

}
void loop() {
  // put your main code here, to run repeatedly:

}

OUTPUT

CHAR ARRAY TO OTHER DATA TYPE CONVERSION

This Arduino code will convert data types from char array [] or character array to other, see below

• Convert char array to int in Arduino
• Convert char array to String in Arduino

// https://pijaeducation.com/data-type-conversion-arduino/

#define delcat 2000
#define delsub 1500
#define delexp 1000

int b;
char g[] = {'1', '2', '3', 'D', 'E'};
String j;

void setup() {
  Serial.begin(9600);
  Serial.println("Defined Variables are -");
  Serial.println("int b;");
  Serial.println("char g[] = {'1', '2', '3', 'D', 'E'};");
  Serial.println("String j;");
  Serial.println();


  /* "CHAR ARRAY to OTHER"
    Data type conversion*/
  Serial.println("CHAR ARRAY to OTHER Data type conversion");
  delay(delcat);

  b = atoi(g);
  Serial.print("char array {'1', '2', '3', 'D', 'E'} to int : ");
  delay(delexp);
  Serial.println(b);

  delay(delsub);
  j = String(g);
  Serial.print("char array {'1', '2', '3', 'D', 'E'} to String : ");
  delay(delexp);
  Serial.println(j);
  Serial.println();


}
void loop() {
  // put your main code here, to run repeatedly:

}

OUTPUT

STRING TO OTHER DATA TYPE CONVERSION

This Arduino code will convert data types from String to other, see below

• Convert String to int in Arduino
• Convert String to char array [] (character array) in Arduino
• Convert String to const char * in Arduino

// https://pijaeducation.com/data-type-conversion-arduino/

#define delcat 2000
#define delsub 1500
#define delexp 1000

int b;
char h[5];
String i = "92AB1";
const char *k;

void setup() {
  Serial.begin(9600);
  Serial.println("Defined Variables are -");
  Serial.println("int b;");
  Serial.println("char h[5];");
  Serial.println("String i = \"92AB1\";");
  Serial.println("const char *k;");
  Serial.println();


  /* "String to OTHER"
    Data type conversion*/
  Serial.println("String to OTHER Data type conversion");
  delay(delcat);

  b = i.toInt();
  Serial.print("String 92AB1 to Int : ");
  delay(delexp);  
  Serial.println(b);

  delay(delsub);
  i.toCharArray(h, 10); // buffer (variable in which to store), max length of buffer can be
  Serial.print("String 92AB1 to Char Array : ");
  delay(delexp);  
  Serial.println(h);

  delay(delsub);
  k = i.c_str();
  Serial.print("String 92AB1 to Const char* : ");
  delay(delexp);  
  Serial.println(k);
  Serial.println();


}

void loop() {
  // put your main code here, to run repeatedly:

}

OUTPUT

CONST CHAR TO STRING CONVERSION

This Arduino code will convert data types from String to other, see below

• Convert const char * to String in Arduino

// https://pijaeducation.com/data-type-conversion-arduino/

#define delcat 2000
#define delsub 1500
#define delexp 1000

String j;
const char *l = "HELLO";

void setup() {
  Serial.begin(9600);
  Serial.println("Defined Variables are -");
  Serial.println("String j;");
  Serial.println("const char *l = \"HELLO\";");
  Serial.println();


  /* "Const char to OTHER"
    Data type conversion*/
  Serial.println("Const char to OTHER Data type conversion");
  delay(delcat);

  j = String(l);
  Serial.print("Const Char to String : ");
  delay(delexp);  
  Serial.println(j);
  Serial.println();

}

void loop() {

}