查询某个字符在字符串中出现的次数

查询某个字符在字符串中出现的次数，可用于查询string,char类型的查询，然后用类模板实现了

 
 
   
   
   
   

  
  #include "iostream"
 
 
   
   
   
   
 
 
   
   
   
   

  
  using 
  
  namespace 
  
  std
  
  ;
 
 
   
   
   
   
 
 
   
   
   
   

  
  
    
    
    
    

 
 
   
   
   
   
 
 
   
   
   
   

  
  //字符串查询某个字符的出现的次数
 
 
   
   
   
   
 
 
   
   
   
   

  
  int 
  
  count
  
  (
  
  const 
  
  string 
  
  &
  
  s
  
  , 
  
  char 
  
  c
  
  )
 
 
   
   
   
   
 
 
   
   
   
   

  
  {
 
 
   
   
   
   
 
 
   
   
   
   
	
  
  int 
  
  n 
  
  = 
  
  0
  
  ;
 
 
   
   
   
   
 
 
   
   
   
   
	
  
  string
  
  ::
  
  const_iterator 
  
  i 
  
  = 
  
  find
  
  (
  
  s
  
  .
  
  begin
  
  (), 
  
  s
  
  .
  
  end
  
  (), 
  
  c
  
  );
 
 
   
   
   
   
 
 
   
   
   
   
	
  
  while 
  
  (
  
  i 
  
  != 
  
  s
  
  .
  
  end
  
  ())
 
 
   
   
   
   
 
 
   
   
   
   
	
  
  {
 
 
   
   
   
   
 
 
   
   
   
   
		
  
  ++
  
  n
  
  ;
 
 
   
   
   
   
 
 
   
   
   
   
		
  
  i 
  
  = 
  
  find
  
  (
  
  i 
  
  + 
  
  1
  
  , 
  
  s
  
  .
  
  end
  
  (), 
  
  c
  
  );
 
 
   
   
   
   
 
 
   
   
   
   
	
  
  }
 
 
   
   
   
   
 
 
   
   
   
   
	
  
  return 
  
  n
  
  ;
 
 
   
   
   
   
 
 
   
   
   
   

  
  }
 
 
   
   
   
   
 
 
   
   
   
   

  
  
    
    
    
    

 
 
   
   
   
   
 
 
   
   
   
   

  
  //类模板的实例化查询模板类出现的次数
 
 
   
   
   
   
 
 
   
   
   
   

  
  template
  
  <
  
  class 
  
  C
  
  , 
  
  class 
  
  T
  
  >
  
  int 
  
  Count
  
  (
  
  const 
  
  C 
  
  &
  
  v
  
  , 
  
  T 
  
  val
  
  )
 
 
   
   
   
   
 
 
   
   
   
   

  
  {
 
 
   
   
   
   
 
 
   
   
   
   
	
  
  typename 
  
  C
  
  ::
  
  const_iterator 
  
  i 
  
  = 
  
  find
  
  (
  
  v
  
  .
  
  begin
  
  (), 
  
  v
  
  .
  
  end
  
  (), 
  
  val
  
  );
 
 
   
   
   
   
 
 
   
   
   
   

  
  
    
    
    
    

 
 
   
   
   
   
 
 
   
   
   
   
	
  
  int 
  
  n 
  
  = 
  
  0
  
  ;
 
 
   
   
   
   
 
 
   
   
   
   
	
  
  while 
  
  (
  
  i 
  
  != 
  
  v
  
  .
  
  end
  
  ())
 
 
   
   
   
   
 
 
   
   
   
   
	
  
  {
 
 
   
   
   
   
 
 
   
   
   
   
		
  
  ++
  
  n
  
  ;
 
 
   
   
   
   
 
 
   
   
   
   
		
  
  ++
  
  i
  
  ;
 
 
   
   
   
   
 
 
   
   
   
   
		
  
  i 
  
  = 
  
  find
  
  (
  
  i
  
  , 
  
  v
  
  .
  
  end
  
  (), 
  
  val
  
  );
 
 
   
   
   
   
 
 
   
   
   
   

  
  
    
    
    
    

 
 
   
   
   
   
 
 
   
   
   
   
	
  
  }
 
 
   
   
   
   
 
 
   
   
   
   
	
  
  return 
  
  n
  
  ;
 
 
   
   
   
   
 
 
   
   
   
   

  
  }
 
 
   
   
   
   
 
 
   
   
   
   

  
  
    
    
    
    

 
 
   
   
   
   
 
 
   
   
   
   

  
  
    
    
    
    

 
 
   
   
   
   
 
 
   
   
   
   

  
  void 
  
  main
  
  ()
 
 
   
   
   
   
 
 
   
   
   
   

  
  {
 
 
   
   
   
   
 
 
   
   
   
   
	
  
  const 
  
  string 
  
  str 
  
  = 
  
  "abcabcdfsafascfaf"
  
  ;
 
 
   
   
   
   
 
 
   
   
   
   
	
  
  char 
  
  c 
  
  = 
  
  'c'
  
  ;
 
 
   
   
   
   
 
 
   
   
   
   
	
  
  int 
  
  n 
  
  = 
  
  Count
  
  (
  
  str
  
  , 
  
  c
  
  );
 
 
   
   
   
   
 
 
   
   
   
   
	
  
  int 
  
  b 
  
  = 
  
  count
  
  (
  
  str
  
  , 
  
  c
  
  );
 
 
   
   
   
   
 
 
   
   
   
   
	
  
  cout 
  
  << 
  
  "字符串里面出现c的个数是：" 
  
  << 
  
  n 
  
  << 
  
  endl
  
  ;
 
 
   
   
   
   
 
 
   
   
   
   

  
  
    
    
    
    

 
 
   
   
   
   
 
 
   
   
   
   

  
  
    
    
    
    

 
 
   
   
   
   
 
 
   
   
   
   
	
  
  system
  
  (
  
  "pause"
  
  );
 
 
   
   
   
   
 
 
   
   
   
   

  
  }