Display a variable as 4 digit number

// Declaration of variables
int a = 0;
unsigned long b = 0;
float c = 0;

// Method: 1
    // Display a 
         if ( a < 10){ Serial.print("0000");}
    else if ( a < 100){ Serial.print("000");}
    else if ( a < 1000){ Serial.print("00");}
    else if ( a < 10000){ Serial.print("0");}
    Serial.print(a);
    
    // Display b
         if ( b < 10){ Serial.print("0000");}
    else if ( b < 100){ Serial.print("000");}
    else if ( b < 1000){ Serial.print("00");}
    else if ( b < 10000){ Serial.print("0");}
    Serial.print(b);
    
    // Display c
         if ( c < 10){ Serial.print("    ");}
    else if ( c < 100){ Serial.print("   ");}
    else if ( c < 1000){ Serial.print("  ");}
    else if ( c < 10000){ Serial.print(" ");}
    Serial.print(c);
    
// Methode: 2

  char Numa [11] ; // large enough for biggest long int
  char Numb [11];
  char Numc [11];
  sprintf (buf, "%04i", a) ;  // leading zeroes, at least 4 chars.
  sprintf (buf, "%04i", b) ;  // leading zeroes, at least 4 chars.
  sprintf (buf, "%04i", c) ;  // leading zeroes, at least 4 chars.
  Serial.print (Numa) ;
  Serial.print (Numb) ;
  Serial.print (Numc) ;