Change code to work with 20x4 LCD instead of 16x2

The error after inserting code...

Arduino: 1.8.13 (Windows 10), Board: "Arduino Uno"

C:\Users\crazy\Documents\Arduino\LCD_FFT_Spectrum_analyzer_20x4_Forum_Help\LCD_FFT_Spectrum_analyzer_20x4_Forum_Help.ino: In function 'void loop()':

LCD_FFT_Spectrum_analyzer_20x4_Forum_Help:137:3: error: 'decay' was not declared in this scope

decay(1);

^~~~~

C:\Users\crazy\Documents\Arduino\LCD_FFT_Spectrum_analyzer_20x4_Forum_Help\LCD_FFT_Spectrum_analyzer_20x4_Forum_Help.ino:137:3: note: suggested alternative: 'delay'

decay(1);

^~~~~

delay

C:\Users\crazy\Documents\Arduino\LCD_FFT_Spectrum_analyzer_20x4_Forum_Help\LCD_FFT_Spectrum_analyzer_20x4_Forum_Help.ino: In function 'void Two16_LCD()':

LCD_FFT_Spectrum_analyzer_20x4_Forum_Help:159:5: error: 'peak_2' was not declared in this scope

 peak_2 = peaks[x] - 8;

 ^~~~~~

C:\Users\crazy\Documents\Arduino\LCD_FFT_Spectrum_analyzer_20x4_Forum_Help\LCD_FFT_Spectrum_analyzer_20x4_Forum_Help.ino:159:5: note: suggested alternative: 'peaks'

 peak_2 = peaks[x] - 8;

 ^~~~~~

 peaks

LCD_FFT_Spectrum_analyzer_20x4_Forum_Help:160:25: error: no matching function for call to 'LiquidCrystal::write(float&, int)'

 lcd.write(peaks[x],0); // print on 1st row

                     ^

In file included from C:\Users\crazy\Documents\Arduino\LCD_FFT_Spectrum_analyzer_20x4_Forum_Help\LCD_FFT_Spectrum_analyzer_20x4_Forum_Help.ino:12:0:

C:\Program Files (x86)\Arduino\libraries\LiquidCrystal\src/LiquidCrystal.h:83:18: note: candidate: virtual size_t LiquidCrystal::write(uint8_t)

virtual size_t write(uint8_t);

              ^~~~~

C:\Program Files (x86)\Arduino\libraries\LiquidCrystal\src/LiquidCrystal.h:83:18: note: candidate expects 1 argument, 2 provided

In file included from C:\Program Files (x86)\Arduino\hardware\arduino\avr\cores\arduino/Stream.h:26:0,

             from C:\Program Files (x86)\Arduino\hardware\arduino\avr\cores\arduino/HardwareSerial.h:29,

             from C:\Program Files (x86)\Arduino\hardware\arduino\avr\cores\arduino/Arduino.h:233,

             from sketch\LCD_FFT_Spectrum_analyzer_20x4_Forum_Help.ino.cpp:1:

C:\Program Files (x86)\Arduino\hardware\arduino\avr\cores\arduino/Print.h:57:12: note: candidate: size_t Print::write(const char*, size_t)

 size_t write(const char *buffer, size_t size) {

        ^~~~~

C:\Program Files (x86)\Arduino\hardware\arduino\avr\cores\arduino/Print.h:57:12: note: no known conversion for argument 1 from 'float' to 'const char*'

C:\Program Files (x86)\Arduino\hardware\arduino\avr\cores\arduino/Print.h:56:20: note: candidate: virtual size_t Print::write(const uint8_t*, size_t)

 virtual size_t write(const uint8_t *buffer, size_t size);

                ^~~~~

C:\Program Files (x86)\Arduino\hardware\arduino\avr\cores\arduino/Print.h:56:20: note: no known conversion for argument 1 from 'float' to 'const uint8_t* {aka const unsigned char*}'

C:\Program Files (x86)\Arduino\hardware\arduino\avr\cores\arduino/Print.h:52:12: note: candidate: size_t Print::write(const char*)

 size_t write(const char *str) {

        ^~~~~

C:\Program Files (x86)\Arduino\hardware\arduino\avr\cores\arduino/Print.h:52:12: note: candidate expects 1 argument, 2 provided

LCD_FFT_Spectrum_analyzer_20x4_Forum_Help:179:21: error: 'freeRam' was not declared in this scope

 Serial.println( freeRam(), DEC);

                 ^~~~~~~

C:\Users\crazy\Documents\Arduino\LCD_FFT_Spectrum_analyzer_20x4_Forum_Help\LCD_FFT_Spectrum_analyzer_20x4_Forum_Help.ino:179:21: note: suggested alternative: 'fread'

 Serial.println( freeRam(), DEC);

                 ^~~~~~~

                 fread

LCD_FFT_Spectrum_analyzer_20x4_Forum_Help:186:16: error: a function-definition is not allowed here before '{' token

int freeRam () {

            ^

LCD_FFT_Spectrum_analyzer_20x4_Forum_Help:193:27: error: a function-definition is not allowed here before '{' token

void decay(int decayrate) {

                       ^

LCD_FFT_Spectrum_analyzer_20x4_Forum_Help:204:1: error: expected '}' at end of input

}

^

Multiple libraries were found for "LiquidCrystal.h"

Used: C:\Program Files (x86)\Arduino\libraries\LiquidCrystal

Not used: C:\Users\crazy\Documents\Arduino\libraries\LiquidCrystal-master

Not used: C:\Users\crazy\Documents\Arduino\libraries\NewLiquidCrystal_lib

exit status 1

'decay' was not declared in this scope

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