Convert serial.read() into a useable string using Arduino?

I'm using two Arduinos to sent plain text strings to each other using newsoftserial and an RF transceiver.

Each string is perhaps 20-30 characters in length. How do I convert Serial.read() into a string so I can do if x == "testing statements", etc.?

Unlimited string readed:

String content = "";
char character;
    
while(Serial.available()) {
     character = Serial.read();
     content.concat(character);
}
      
if (content != "") {
     Serial.println(content);
}

From Help with Serial.Read() getting string:

char inData[20]; // Allocate some space for the string
char inChar=-1; // Where to store the character read
byte index = 0; // Index into array; where to store the character

void setup() {
    Serial.begin(9600);
    Serial.write("Power On");
}

char Comp(char* This) {
    while (Serial.available() > 0) // Don't read unless
                                       // there you know there is data
    {
       if(index < 19) // One less than the size of the array
       {
           inChar = Serial.read(); // Read a character
           inData[index] = inChar; // Store it
           index++; // Increment where to write next
           inData[index] = '\0'; // Null terminate the string
       }
    }

    if (strcmp(inData,This)  == 0) {
       for (int i=0;i<19;i++) {
            inData[i]=0;
       }
       index=0;
       return(0);
    }
    else {
       return(1);
    }
}

void loop()
{
    if (Comp("m1 on")==0) {
        Serial.write("Motor 1 -> Online\n");
    }
    if (Comp("m1 off")==0) {
       Serial.write("Motor 1 -> Offline\n");
    }
}

You can use Serial.readString() and Serial.readStringUntil() to parse strings from Serial on the Arduino.

You can also use Serial.parseInt() to read integer values from serial.

int x;
String str;
    
void loop() 
{
     if(Serial.available() > 0)
     {
        str = Serial.readStringUntil('\n');
        x = Serial.parseInt();
     }
}

The value to send over serial would be my string\n5 and the result would be str = "my string" and x = 5

I was asking the same question myself and after some research I found something like that.

It works like a charm for me. I use it to remote control my Arduino.

// Buffer to store incoming commands from serial port
String inData;
    
void setup() {
    Serial.begin(9600);
    Serial.println("Serial conection started, waiting for instructions...");
}
    
void loop() {
    while (Serial.available() > 0)
    {
        char recieved = Serial.read();
        inData += recieved; 
    
        // Process message when new line character is recieved
        if (recieved == '\n')
        {
            Serial.print("Arduino Received: ");
            Serial.print(inData);
                
            // You can put some if and else here to process the message juste like that:

            if(inData == "+++\n"){ // DON'T forget to add "\n" at the end of the string.
              Serial.println("OK. Press h for help.");
            }   

    
            inData = ""; // Clear recieved buffer
        }
    }
}

This would be way easier:

char data [21];
int number_of_bytes_received;

if(Serial.available() > 0)
{
    number_of_bytes_received = Serial.readBytesUntil (13,data,20); // read bytes (max. 20) from buffer, untill <CR> (13). store bytes in data. count the bytes recieved.
    data[number_of_bytes_received] = 0; // add a 0 terminator to the char array
} 

bool result = strcmp (data, "whatever");
// strcmp returns 0; if inputs match.
// http://en.cppreference.com/w/c/string/byte/strcmp


if (result == 0)
{
   Serial.println("data matches whatever");
} 
else 
{
   Serial.println("data does not match whatever");
}

Convert serial.read() into a useable string using Arduino?

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