C Language K&r Exercise series-Four ways to replace multiple spaces in a single space in a sentence

Original question:

Write a program to copy its input to its output, replacing each string of one or more blanks by a single blank.

The first type:

This is most commonly used to set a inspace as a Boolean variable that flags whether the current input is in a character, or outside of a character

#include <stdio.h>  int main (void) {  int c;  int inspace=0;    while ((c = GetChar ()) = EOF)  {    if (c = = ")    {      if (InSpace = = 0)      {        inspace = 1;        Putchar (c);      }    }    else    {      inspace = 0;      Putchar (c);    }  }    return 0;}

The second kind: own thought, although the effect is similar, but the mentality is different

Number as the flag bit, record the amount of space

#include < stdio.h > main (void) {    int c;    int number;    Number = 0;       Initialization space Numbers           while ((c = GetChar ()) = EOF)    {        if (c = = ')        {            ++number;            if (number = = 1)                Putchar (c);        }        if (c! = ")        {            Putchar (c);            Number = 0;        }    }    return 0; }

The third type:

Use a while loop to "take" multiple spaces

#include < stdio.h >main (void) {    int c;    while ((c = GetChar ()) = EOF)    {        if (' = = c)        {            Putchar (c);            while ((c = GetChar ()) = = "&& c! = EOF)                ;        }         if (EOF = = c) break            ;         Putchar (c);    }    return 0;}

The fourth type:

Use a character pc as the character before the "current character" to determine whether the trailing space is output by the PC

#include <stdio.h>int main () {        int c, PC;           PC = EOF;          while ((c = GetChar ()) = EOF) {                if (c = = ")                        if (PC! =")                                   Putchar (c);                  if (c! = ")                        Putchar (c);                PC = C;        }          return 0;}

C Language K&r Exercise series-Four ways to replace multiple spaces with a single space in a sentence