字符串操作（连接、查找、截断、反转、大小写转换）

 

1：字符串连接

string strSample1("Hello");

string strSample2("String!");

string strSample3("strSample3");

strSample1+= strSample2;

strSample1.append(strSample3);

2：字符串查找

string strSample("Good dayString! Today is beautiful!");

size_t nOffset = strSample.find("day",2);//从下标2开始查找

if(nOffset != npos)

{

  cout << "在下标：" << nOffset << "找到了day!" << endl;

}

else

{

   cout << "没找到!" << endl;

}

找出所有的day

size_t nSubstringOffset = strSample.find("day",0);//从头开始查找

while(nSubstringOffset != npos)

{

   cout << "在下标：" << nSubstringOffset << "找到了day!" << endl;

   size_t nSearchOffset= nSubstringOffset+1;

   nSubstringOffset = strSample.find("day",nSearchOffset);

}
3：字符串截断

string strSample("Good dayString! Today is beautiful!");

strSample.erase(5,18);//Good is beautiful!

4:字符串反转

string strSample("Good dayString! Today is beautiful!");

reverse(strSample.begin(),strSample.end());

5:字符串大小写转换

string strSample("Good dayString! Today is beautiful!");

transform(strSample.begin(),strSample.end(),strSample.begin(),toupper);

string strSample1("Hello");

string strSample2("String!");

string strSample3("strSample3");

strSample1+= strSample2;

strSample1.append(strSample3);

2：字符串查找

string strSample("Good dayString! Today is beautiful!");

size_t nOffset = strSample.find("day",2);//从下标2开始查找

if(nOffset != npos)

{

  cout << "在下标：" << nOffset << "找到了day!" << endl;

}

else

{

   cout << "没找到!" << endl;

}

找出所有的day

size_t nSubstringOffset = strSample.find("day",0);//从头开始查找

while(nSubstringOffset != npos)

{

   cout << "在下标：" << nSubstringOffset << "找到了day!" << endl;

   size_t nSearchOffset= nSubstringOffset+1;

   nSubstringOffset = strSample.find("day",nSearchOffset);

}
3：字符串截断

string strSample("Good dayString! Today is beautiful!");

strSample.erase(5,18);//Good is beautiful!

4:字符串反转

string strSample("Good dayString! Today is beautiful!");

reverse(strSample.begin(),strSample.end());

5:字符串大小写转换

string strSample("Good dayString! Today is beautiful!");

transform(strSample.begin(),strSample.end(),strSample.begin(),toupper);

6:buf中查询字符e

int main()
{
	char buf[] = " hellow"; 
	char *p = strchr(buf,'e');
	if (NULL == p)
	{
		printf("查询失败\n");//查询失败返回NULL
	} 
	else
	{
		printf("p = %s\n",p);//buf中查询字符e,存在返回p的地址,ellow
	}
}

 

 

7:buf中查询字串ell

int main()
{
	char buf[] = " hellow"; 
	char *p = strstr(buf,"ell");
	if (NULL == p)
	{
		printf("查询失败\n");//查询失败返回NULL
	} 
	else
	{
		printf("p = %s\n",p);//buf中查询字串ell,存在返回p的地址,ellow
	}
}

8:字符串分割

int main()
{
	char buf[] = "abd,mike,efg,hellow"; 
	char tmp[100]; 
	strcmp(tmp,buf);

	char *p;
	p = strtok(tmp,","); // 第一次调用
	while (p != NULL)
	{
		printf("p = %s\n",p);// p = abd,p = mike,p = efg,p = hellow
		p = strtok(NULL,","); //第二次起，第一个参数需要写NULL
	}
}

9：字符串替换

Void StringReplace(string &strBase, string strSrc, string strDes)
{
	string::size_type pos = 0;
	string::size_type srcLen = strSrc.size();
	string::size_type desLen = strDes.size();
	pos=strBase.find(strSrc, pos); 
	while ((pos != string::npos))
	{
		strBase.replace(pos, srcLen, strDes);
		pos=strBase.find(strSrc, (pos+desLen));
	}
}