C++string类常见用法（一）

2019-11-06 08:48:48

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这是第一部分。和其他博客一样，我还是采用代码方式描述，引入，具体细节请查询文档或根据代码推测，编译运行。 - 赋值 - 数据处理 - 迭代，遍历 - 一些常用辅助性函数

#include<iostream>#include<string>using namespace std;int main(){ string str = "str"; str.push_back('i'); cout<<str.size()<<" "<<str.length()<<" "<<str.max_size()<<endl; for(string::iterator iter = str.begin() ; iter != str.end();iter++) cout<<(*iter); cout<<endl; bool empty = true; empty = str.empty(); cout <<"that str is empty is "<<boolalpha<<empty<<endl;} //添加库string//使用push_back来增加元素//使用size或length得出string的长度//使用迭代器来进行简易的输出 //使用empty()函数判断是否非空 #include<iostream>#include<string>using namespace std;int main(){//part1 赋值 string str1 = "RALPHFJY"; string str2 = "FUNKYA"; str1 = str2; cout<<str1; cout<<endl; str1.assign("RALPHFJY LOVE FUNKTA"); cout<<str1; cout<<endl; str1.assign("RALPHFJY LOVE FUNKYA",9,4); //begin and number cout<<str1<<endl; str1.assign("RALPHFJY LOVE FUNKTA",14); cout<<str1<<endl; char temp[] ="we are together"; str1.assign(temp); cout<<str1<<endl; str1.assign(temp,2); cout<<str1<<endl; str1.assign(temp,0,2); cout<<str1<<endl; string ptr; ptr.assign(5,'!'); //赋值 cout<<ptr<<endl;} } //由上可见一些典型的string类赋值方法 // #include<iostream>#include<string>#include<algorithm>using namespace std;int main(){ string str = "RALPHFJY"; for(int index = 0 ; index <str.size();index++) cout<<str.at(index); cout<<endl; cout<<str.front()<<endl; cout<<str.back()<<endl; const char *ptr = str.data(); cout<<(*ptr)<<endl; cout<<str.c_str()<<endl; //returns a non-modifiable standard C character array version of the string for(string::iterator iter = str.begin() ; iter != str.end() ; iter++) cout<<(*iter); cout<<endl; for(string::const_iterator iter = str.cbegin() ; iter != str.cend() ; iter++) cout<<(*iter); cout<<endl; /*for(string::iterator iter = str.rbegin() ; iter != str.rend() ; iter++) cout<<(*iter); cout<<endl; */ reverse(str.begin(),str.end()); cout<<str<<endl; str.clear(); cout<<str<<endl; cout<<"finished"<<endl;}//使用迭代器等方法进行遍历//使用reverse #include<iostream>#include<string>using namespace std;int main(){ string str; str.push_back('1'); str.pop_back(); cout<<"finished"<<endl; cout<<str<<endl; str.push_back('1'); str.push_back('2'); cout<<str<<endl; str.insert(1,1,'3'); cout<<str<<endl; str.assign("12"); str.insert(1,2,'3'); //index ,copy number,character cout<<str<<endl; str.assign("abcdefg"); str.erase(0,2); cout<<str<<endl; str.assign("abcdefg"); str.erase(2,4); cout<<str<<endl; string::iterator it = str.begin()+1 ; str.assign("abcdefg"); str.erase(it); cout<<str<<endl; str.assign("abcdefg"); str.append(); cout<<str<<endl;}//一些数据操作

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