HOw to detect the flow of water through a pipe

Using Arduino Sensors
14

Hmmm...what version of the IDE are you running?

I tried to give your code a whirl on a spare Arduino but it exploded (see below)

watermeter.cpp: In function 'void loop()':
watermeter:43: error: 'outbufferIdx' was not declared in this scope
watermeter:45: error: 'OutTitle' was not declared in this scope
watermeter:51: error: 'outbuffer' was not declared in this scope
watermeter.cpp: In function 'void OutBufferPrint(int, long unsigned int, long unsigned int)':
watermeter:66: error: 'outbufferIdx' was not declared in this scope
watermeter:66: error: 'OUTBUFFER_SIZE' was not declared in this scope
watermeter:69: error: 'outbuffer' was not declared in this scope
watermeter:69: error: 'outbufferIdx' was not declared in this scope
watermeter:73: error: expected `}' at end of input