EDIT
After trying to use the @Majenko's answer I sometimes get garbage values printed. Any ideas why?
float a = analogRead(A1) / 1023.;
float b = analogRead(A2) / 1023.;
bool c = analogRead(A3) / 1023;
char* output = createString(a, b, c);
Serial.println(output);
char* createString (float _a, float _b, bool _c)
{
char a_string[5];
dtostrf(_a, 4, 1, a_string);
char b_string[5];
dtostrf(_b, 4, 1, b_string);
char out[12];
snprintf(out, 12, "%4s %4s %d", a_string, b_string, c ? 1 : 0);
return out;
}
and the output:
0.6 1.0 0
0.6 1.0 0
0.6 1.0 0
0.6 1.0 0
0.6 1.0 0
0.6 1.0 0
0.�tS
�
0.6 `S
�
0.6 1.0
}
0.6 1.0 0
0.7 1.0 0
0.6 1.0 0
0.6 1.0 0
using
Serial.print(a_string);
Serial.print(" ");
Serial.print(b_string);
Serial.print(" ");
Serial.println(c);
doesn't produce the errors
EDIT
After trying to use the @Majenko's answer I sometimes get garbage values printed. Any ideas why?
float a = analogRead(A1) / 1023.;
float b = analogRead(A2) / 1023.;
bool c = analogRead(A3) / 1023;
char* output = createString(a, b, c);
Serial.println(output);
char* createString (float _a, float _b, bool _c)
{
char a_string[5];
dtostrf(_a, 4, 1, a_string);
char b_string[5];
dtostrf(_b, 4, 1, b_string);
char out[12];
snprintf(out, 12, "%4s %4s %d", a_string, b_string, c ? 1 : 0);
return out;
}
and the output:
0.6 1.0 0
0.6 1.0 0
0.6 1.0 0
0.6 1.0 0
0.6 1.0 0
0.6 1.0 0
0.�tS
�
0.6 `S
�
0.6 1.0
}
0.6 1.0 0
0.7 1.0 0
0.6 1.0 0
0.6 1.0 0
using
Serial.print(a_string);
Serial.print(" ");
Serial.print(b_string);
Serial.print(" ");
Serial.println(c);
doesn't produce the errors
build fixed size strings from floats
This is likely a duplicate, but I couldn't find the original question. This is really basic, but just can't figure it out.
I'm trying to combine a few char arrays together. This is what I've tried so far.
float a = 12.3456;
float b = 5.4321;
bool c = true;
char a_string[4];
dtostrf(a, 4, 1, a_string);
char b_string[4];
dtostrf(b, 4, 1, b_string);
char c_string[2] = {'0', '0円'};
if (c) {
c_string[0] = '1';
}
char output[12] = "-----------";
output[0] = a_string[0];
output[1] = a_string[1];
output[2] = a_string[2];
output[3] = a_string[3];
output[4] = ' ';
output[5] = b_string[0];
output[6] = b_string[1];
output[7] = b_string[2];
output[8] = b_string[3];
output[9] = ' ';
output[10] = c_string[0];
Serial.println(output);
Results in an empty string in seems.
If I remove the second dtostrf(), and change b_string[0] ... to a_string[0] Then I get 12.3 12.3 1. Doesn't seem to like having dtostrf() called more than once, but it seems like the function I want, since it allows me to set a fixed strint size. The output I'd be looking for is 12.3 5.4 1
another approach
String a_string = String(a, 1);
String b_string = String(b, 1);
String c_string = String(c);
String output;
String space = " ";
output.concat(a_string);
output.concat(space);
output.concat(b_string);
output.concat(space);
output.concat(c_string);
Serial.println(output);
This outputs 12.3 5.4 1. Is there a way to make the String fixed width? I'm looking for
12.3 5.4 1 instead of
12.3 5.4 1
What's the proper way of doing this?