C语言实现从字符串中计算单词个数，使用状态法

 代码：

#include
#include
#include
#include
#include
#include

#define BEGIN    1
#define INWORD   2
#define OUTWORD  3
#define END      4

//状态模式

int getwordnum(const char* str)
{
    assert(str!=nullptr);
    int num=0;
    int tag=BEGIN;
    for(const char* p=str;*p!='';++p)
    {
        switch(tag)
        {
            case BEGIN:
            {
                if(isalpha(*p))
                {
                   tag=INWORD; 
                }
                else{
                    tag=OUTWORD;
                }
                break;
                
            }
            case INWORD:
            {
                if(!(isalpha(*p)||*p=='''||*p=='-'))
                {
                    tag=OUTWORD;
                    num+=1;
                }
                break;
            }
            case OUTWORD:
            {
                if(isalpha(*p))
                {
                    tag=INWORD;
                }
                break;
            }
        }
    }
    if(tag==INWORD)
    {
        num+=1;
    }
    return num;
}

int main()
{
    char str1[]={"The heart of the Mingw-w64 project is headers and support libraries to run the output of GCC on Windows. Since Mingw-w64 is neither the home of GCC nor of binutils, several sets of installation packages which combine them are available."};
    char str2[]={" The heart of the Mingw-w64 project is headers and support libraries to run the output of GCC on Windows. Since Mingw-w64 is neither the home of GCC nor of binutils, several sets of installation packages which combine them are available.  "};
    int num1=getwordnum(str1);
    int num2=getwordnum(str2);
    printf("%d %dn",num1,num2);
    return 0;
}

结果：

40 40