errors on working code?

i copied a working code to test a 7led display (8including decimal) but i keep getting error messages that dont seem to make sense i dont see what the error is saying can anyone help me here the code is (with errors to follow)

/*
Make Projects: How to Drive a 7 Segment LED
 URL:
 By: Riley Porter
 This is an introduction on how to drive a 7 Segment LED using only a Arduino.  This is 
 not the best way to do this.  This is meant to be a learning excercise.  In later tutorials
 I will show you how to use an dedicated IC using SPI or a Shift Register.  Enjoy.


 digitalWrite(A, HIGH) = turn off the "A" segment in the LED display
 digitalWrite(B, LOW)  = turn on the "B" segment in the LED display

 */

#define A 8
#define B 9
#define C 2
#define D 3
#define E 4
#define F 5
#define G 6




void clr()
{
  //Clears the LED
  digitalWrite(A, HIGH);
  digitalWrite(B, HIGH);
  digitalWrite(C, HIGH);
  digitalWrite(D, HIGH);
  digitalWrite(E, HIGH);
  digitalWrite(F, HIGH);
  digitalWrite(G, HIGH);

}


void char_A()
{
  digitalWrite(D, HIGH);
  digitalWrite(E, LOW);
  digitalWrite(F, LOW);
  digitalWrite(G, LOW);
  digitalWrite(A, LOW);
  digitalWrite(B, LOW);
  digitalWrite(C, LOW);
}
z
void char_B()
{
  //Displays B
  digitalWrite(D, LOW);
  digitalWrite(E, LOW);
  digitalWrite(F, LOW);
  digitalWrite(G, LOW);
  digitalWrite(A, HIGH);
  digitalWrite(B, HIGH);
  digitalWrite(C, LOW);
}

void char_C()
{
  //Displays C
  digitalWrite(D, LOW);
  digitalWrite(E, LOW);
  digitalWrite(F, LOW);
  digitalWrite(G, HIGH);
  digitalWrite(A, LOW);
  digitalWrite(B, HIGH);
  digitalWrite(C, HIGH);
}

void char_D()
{
  //Displays D
  digitalWrite(D, LOW);
  digitalWrite(E, LOW);
  digitalWrite(F, HIGH);
  digitalWrite(G, LOW);
  digitalWrite(A, HIGH);
  digitalWrite(B, LOW);
  digitalWrite(C, LOW);
}

void char_E()
{
  //Displays E
  digitalWrite(D, LOW);
  digitalWrite(E, LOW);
  digitalWrite(F, LOW);
  digitalWrite(G, LOW);
  digitalWrite(A, LOW);
  digitalWrite(B, HIGH);
  digitalWrite(C, HIGH);
}

void char_F()
{
  //Displays F
  digitalWrite(D, HIGH);
  digitalWrite(E, LOW);
  digitalWrite(F, LOW);
  digitalWrite(G, LOW);
  digitalWrite(A, LOW);
  digitalWrite(B, HIGH);
  digitalWrite(C, HIGH);
}


void one()
{
  //Displays 1
  digitalWrite(D, HIGH);
  digitalWrite(E, LOW);
  digitalWrite(F, LOW);
  digitalWrite(G, HIGH);
  digitalWrite(A, HIGH);
  digitalWrite(B, HIGH);
  digitalWrite(C, HIGH);
}

void two()
{
  //Displays 2
  digitalWrite(D, LOW);
  digitalWrite(E, LOW);
  digitalWrite(F, HIGH);
  digitalWrite(G, LOW);
  digitalWrite(A, LOW);
  digitalWrite(B, LOW);
  digitalWrite(C, HIGH);
}

void three()
{
  //Displays 3
  digitalWrite(D, LOW);
  digitalWrite(E, HIGH);
  digitalWrite(F, HIGH);
  digitalWrite(G, LOW);
  digitalWrite(A, LOW);
  digitalWrite(B, LOW);
  digitalWrite(C, LOW);
}

void four()
{
  //Displays 4
  digitalWrite(D, HIGH);
  digitalWrite(E, HIGH);
  digitalWrite(F, LOW);
  digitalWrite(G, LOW);
  digitalWrite(A, HIGH);
  digitalWrite(B, LOW);
  digitalWrite(C, LOW);
}

void five()
{
  //Displays 5
  digitalWrite(D, LOW);
  digitalWrite(E, HIGH);
  digitalWrite(F, LOW);
  digitalWrite(G, LOW);
  digitalWrite(A, LOW);
  digitalWrite(B, HIGH);
  digitalWrite(C, LOW);
}

void six()
{
  //Displays 6
  digitalWrite(D, LOW);
  digitalWrite(E, LOW);
  digitalWrite(F, LOW);
  digitalWrite(G, LOW);
  digitalWrite(A, LOW);
  digitalWrite(B, HIGH);
  digitalWrite(C, LOW);
}

void seven()
{
  //Displays 7
  digitalWrite(D, HIGH);
  digitalWrite(E, HIGH);
  digitalWrite(F, HIGH);
  digitalWrite(G, HIGH);
  digitalWrite(A, LOW);
  digitalWrite(B, LOW);
  digitalWrite(C, LOW);
}

void eight()
{
  //Displays 8
  digitalWrite(D, LOW);
  digitalWrite(E, LOW);
  digitalWrite(F, LOW);
  digitalWrite(G, LOW);
  digitalWrite(A, LOW);
  digitalWrite(B, LOW);
  digitalWrite(C, LOW);
}

void nine()
{
  //Displays 9
  digitalWrite(D, LOW);
  digitalWrite(E, HIGH);
  digitalWrite(F, LOW);
  digitalWrite(G, LOW);
  digitalWrite(A, LOW);
  digitalWrite(B, LOW);
  digitalWrite(C, LOW);
}

void zero()
{
  //Displays 0
  digitalWrite(D, LOW);
  digitalWrite(E, LOW);
  digitalWrite(F, LOW);
  digitalWrite(G, HIGH);
  digitalWrite(A, LOW);
  digitalWrite(B, LOW);
  digitalWrite(C, LOW);
}

void LoopDisplay()
{
  //Loop through all Chars and Numbers
  char_A();
  delay(1000);
  char_B();
  delay(1000);
  char_C();
  delay(1000);
  char_D();
  delay(1000);
  char_E();
  delay(1000);
  char_F();
  delay(1000);
  one();
  delay(1000);
  two();
  delay(1000);
  three();
  delay(1000);
  four();
  delay(1000);
  five();
  delay(1000);
  six();
  delay(1000);
  seven();
  delay(1000);
  eight();
  delay(1000);
  nine();
  delay(1000);
  zero();
  delay(1000);
}

void setup()
{
  //Setup our pins
  pinMode(A, OUTPUT);
  pinMode(B, OUTPUT);
  pinMode(C, OUTPUT);
  pinMode(D, OUTPUT);
  pinMode(E, OUTPUT);
  pinMode(F, OUTPUT);
  pinMode(G, OUTPUT);
  Serial.begin(9600);  //Begin serial communcation

}

void loop()
{
  0
    Serial.println("Starting\n");
  LoopDisplay();

}

the errors are:

C:\Program Files (x86)\Arduino\hardware\tools\avr\bin\avr-g++ -c -g -Os -Wall -fno-exceptions -ffunction-sections -fdata-sections -mmcu=atmega328p -DF_CPU=16000000L -MMD -DUSB_VID=null -DUSB_PID=null -DARDUINO=105 -IC:\Program Files (x86)\Arduino\hardware\arduino\cores\arduino -IC:\Program Files (x86)\Arduino\hardware\arduino\variants\standard C:\Users\Phillip\AppData\Local\Temp\build3003842349680921945.tmp\sketch_jun11a.cpp -o C:\Users\Phillip\AppData\Local\Temp\build3003842349680921945.tmp\sketch_jun11a.cpp.o In file included from C:\Program Files (x86)\Arduino\hardware\arduino\cores\arduino/Arduino.h:192, from sketch_jun11a.ino:26: C:\Program Files (x86)\Arduino\hardware\arduino\cores\arduino/WString.h:38:1: warning: "F" redefined sketch_jun11a.ino:20:1: warning: this is the location of the previous definition sketch_jun11a:30: error: expected constructor, destructor, or type conversion before 'void' sketch_jun11a.ino: In function 'void clr()': sketch_jun11a:34: error: 'F' was not declared in this scope sketch_jun11a.ino: In function 'void char_A()': sketch_jun11a:44: error: 'F' was not declared in this scope sketch_jun11a.ino: At global scope: sketch_jun11a:51: error: expected constructor, destructor, or type conversion before 'void' sketch_jun11a.ino: In function 'void char_C()': sketch_jun11a:68: error: 'F' was not declared in this scope sketch_jun11a.ino: In function 'void char_D()': sketch_jun11a:80: error: 'F' was not declared in this scope sketch_jun11a.ino: In function 'void char_E()': sketch_jun11a:92: error: 'F' was not declared in this scope sketch_jun11a.ino: In function 'void char_F()': sketch_jun11a:104: error: 'F' was not declared in this scope sketch_jun11a.ino: In function 'void one()': sketch_jun11a:117: error: 'F' was not declared in this scope sketch_jun11a.ino: In function 'void two()': sketch_jun11a:129: error: 'F' was not declared in this scope sketch_jun11a.ino: In function 'void three()': sketch_jun11a:141: error: 'F' was not declared in this scope sketch_jun11a.ino: In function 'void four()': sketch_jun11a:153: error: 'F' was not declared in this scope sketch_jun11a.ino: In function 'void five()': sketch_jun11a:165: error: 'F' was not declared in this scope sketch_jun11a.ino: In function 'void six()': sketch_jun11a:177: error: 'F' was not declared in this scope sketch_jun11a.ino: In function 'void seven()': sketch_jun11a:189: error: 'F' was not declared in this scope sketch_jun11a.ino: In function 'void eight()': sketch_jun11a:201: error: 'F' was not declared in this scope sketch_jun11a.ino: In function 'void nine()': sketch_jun11a:213: error: 'F' was not declared in this scope sketch_jun11a.ino: In function 'void zero()': sketch_jun11a:225: error: 'F' was not declared in this scope sketch_jun11a.ino: In function 'void LoopDisplay()': sketch_jun11a:237: error: 'char_B' was not declared in this scope sketch_jun11a.ino: In function 'void setup()': sketch_jun11a:277: error: 'F' was not declared in this scope sketch_jun11a.ino: In function 'void loop()': sketch_jun11a:286: error: expected `;' before 'Serial' sketch_jun11a.ino:286: warning: statement has no effect

also i had another code i was working on a few days ago that was giving simmilar errors with me not able to see why. i thought it was me being stupid but now that it has happened again. i know it is me being stupid but i figured i would ask for help this time.

What are the following characters doing in your code?

z
  0

In addition to the problem mentioned by @dannable...

#define F 5

...is the culprit. Don't use single letter macros.

void loop()
{
  0
    Serial.println("Starting\n");
  LoopDisplay();

}

check above error in your code