统计一个句子单词的个数

1. 设置标志位实现

#include<iostream>
using namespace std;
int main()
{
	int flag=0;
	int count=0,i=0;
	char str[1000]={0};
	gets(str);
	for (i=0;str[i]!='\0';i++)
	{
		if (str[i]==' ')    //空格设置标志位
		{
			flag=0;
		}
		else if(flag==0)    //非空格，但之前为空格
		{
			count++;
			flag=1;
		}
	}
    printf("%d\n",count);
	system("pause");
    return 0;
}

2.使用strtok函数

#include <iostream>
#include <string>
using namespace std;
int main()
{
	int i=0;
	int count=0;
	char str[1000]={0};
    gets(str);
    while(str[i]!='\0')                     //将非字母字符置成空格
	{
		if ((str[i]>='a'&&str[i]<='z')||(str[i]>='A'&&str[i]<='Z'))
		{
			i++;
		}
		else
		{
			str[i]=' ';
			i++;
		}
	}
 	char *p=strtok(str," ");   //进行字符串分割
	while(p!=NULL)             //统计
	{
       count++;
	   p=strtok(NULL," ");
	}
	printf("%d\n",count);
	system("pause");
	return 0;
}

统计一句话中每个单词出现的次数，考虑重复，但原单词出现顺序统计

#include <iostream>
#include <map>
#include <string>
using namespace std;
struct v_sCount      //保存统计信息
{
	int count;       //单词出现次数
	int v_ipos;      //标识单词出现的顺序
};
int main()
{
	int i=0;
	int pos=1;
	map<string,struct v_sCount> v_mCount;
	map<string,struct v_sCount>::iterator v_pCount;
	char *p=NULL;
	char str[1000]={0};
	gets(str);
	while(str[i]!='\0')   //出去单词中非字母字符
	{
		if ((str[i]>='a'&&str[i]<='z')||(str[i]>='A'&&str[i]<='Z'))
		{
			i++;
		}
		else
		{
			str[i]=' ';
			i++;
		}
	}
    p=strtok(str," ");               //字符串分割函数（按空格） char * strtok(char *s, const char *delim);
	while(p!=NULL)                   //统计出现次数
	{
		string tmp=p;
       v_pCount=v_mCount.find(tmp);
	   if (v_pCount==v_mCount.end())  //第一次出现
	   {
		   struct v_sCount struct_tmp;
		   struct_tmp.count=1;
		   struct_tmp.v_ipos=pos++;
		   v_mCount.insert(pair<string,struct v_sCount>(tmp,struct_tmp));
	   }
	   else                            //已出现，更新值
	   {
		   v_pCount->second.count++;
	   }
	   p=strtok(NULL," ");     //接着取字符串
	}
	//将统计结果输出
	for(i=1;i<pos;i++)
	{
		for(v_pCount=v_mCount.begin();v_pCount!=v_mCount.end();v_pCount++)
		{
			if(v_pCount->second.v_ipos==i)
				cout<<v_pCount->first<<' '<<v_pCount->second.count<<endl;
		}
	}
	system("pause");
	return 0;
}