String split in to variables

Projects Programming
1

Hello,

I am having some problems spliting the folowing string in diferent variables(value1,value2, value3, value4;):

uint8_t* buf = "SENDER_1,20.5,65.4,20";

String value1;
float value2, value3, value4;

sscanf(buf, "%s,%f,%f,%f", &value1, &value2, &value3, &value4);

Serial.println(value1);
Serial.println(value2);
Serial.println(value3);
Serial.println(value4);

when i compile de code give me an error : "error: invalid conversion from 'uint8_t* {aka unsigned char*}' to 'const char*' [-fpermissive]"

I was wondering if any one could help me formulate a function to achieve my goal? Thankyou =)

2

You can use strtok() to parse a comma (or other character) separated character string:

#define MAX_VALS    4

char buf[] = 
    "SENDER_1,20.5,65.4,20";

char 
    *token;
uint8_t 
    idx;
char 
    *pszValues[MAX_VALS];
  
void setup() 
{
    Serial.begin(115200);
    Serial.println( "Starting..." );
    
    idx = 0;
    token = strtok( buf, "," );
    while( token != NULL ) 
    {
        //Serial.println( token );
        if( idx < MAX_VALS )
            pszValues[idx++] = token;
                         
        token = strtok( NULL, "," );
        
    }//while

    Serial.print( "Value 0: "); Serial.println( pszValues[0] );
    float value2 = atof( pszValues[1] );
    Serial.print( "Value 1: "); Serial.println( value2, 1 );
    float value3 = atof( pszValues[2] );
    Serial.print( "Value 2: "); Serial.println( value3, 1 );
    float value4 = atof( pszValues[3] );
    Serial.print( "Value 3: "); Serial.println( value4, 1 );
    
}//setup

void loop() 
{
}//loop

I'd avoid the use of capital-S Strings in Arduino projects due to the potential for memory usage issues.

3

Once strtok() separates the pieces use atof() on the float strings to convert them to float numbers, if necessary.

4

there are two problems

  • sscanf() is designed to be used with c strings not String. define char value1 [20]
    char value1 [20];
  • c++ wants string constants to be defined as "const char"
const char * buf = "SENDER_1,20.5,65.4,20";
5

The default Arduino configuration does not support floating point operations for, amongst others, sscanf():

6

Thank you very much...... its working. :slight_smile: