[My C language interview series] 013 word-based flip string

[My C language interview series] 013 word-based flip string

Flipped string in words

Original question: Write a function string reverse string word by word (string input) that reverses a string word by word.

For instance:

"The house is blue" --> "Blue is house"

"Zed is dead" --> "Dead is zed"

"All-in-One" --> "All-in-One"

Without adding any auxiliary array space, we can solve this problem:

Method 1:

1, Flip the entire string.

2, Flip every word.

Method 2:

1, Flip every word.

2, Flip the entire string.

Method 1 and method 2 are actually sequential issues, without affecting the time or space complexity of the algorithm.

 

The following code is provided: [this program is compiled in Dev C ++ 4.9.9.2]

# Include <stdio. h>

 

# Define is_print (CH)> 0x20 & (CH) <0x7e) // parse t Space

 

Char * reverseeveryword (char * Str );

Char * reversewholestring (char * Str );

Char * lr_reverse (char * left, char * right );

 

Int main (void)

{

Char STR [] = "Hello word! **";

Char * P = STR;

# If 0

Reversewholestring (STR );

Reverseeveryword (STR );

Puts (STR );

# Else

Reverseeveryword (STR );

Reversewholestring (STR );

Puts (STR );

# Endif

System ("pause ");

Return 0;

}

Char * reverseeveryword (char * Str)

{

Char * Right = STR, * Left = STR;

If (STR = NULL)

Return NULL;

While (! Is_print (* right ))

Right ++;

While (* right)

{

Left = right;

While (is_print (* right ))

Right ++;

Lr_reverse (left, right-1 );

While (* Right &&! Is_print (* right ))

Right ++;

}

Return STR;

}

Char * reversewholestring (char * Str)

{

Char * P = STR;

If (STR = NULL)

Return NULL;

While (* P) P ++;

P --;

Lr_reverse (STR, P );

Return STR;

}

Char * lr_reverse (char * left, char * right)

{

Char TT, * ret = left;

If (Left = NULL | right = NULL)

Return NULL;

While (left <right)

{

Tt = * left;

* Left ++ = * right;

* Right -- = tt;

}

Return ret;

}