C++primer_順序容器之string操作

本例以代碼形式整理了C++primer第九章string操作的基本函數方法，其中每個函數 的作用在代碼註釋中解釋到位，若是仍有疑惑，請仔細閱讀課本習題

#include <iostream>
#include<string>
#include<vector>
using namespace  std;
void replace_string(string &s, const string &oldVal, const string &newVal)//最原始的字符串迭代器進行對比替換
{
    auto l = oldVal.size();
    if (!l)
        return;
    auto iter = s.begin();
    while (iter <= s.end() - 1)
    {
        auto iter1 = iter;
        auto iter2 = oldVal.begin();
        while (iter2 !=oldVal.end()&& *iter1==*iter2)
        {
            iter1++;
            iter2++;    
        }
        if (iter2 == oldVal.end())
        {
            iter = s.erase(iter, iter1);
            if (newVal.size())
            {
                iter2 == newVal.end();//出現錯誤直接崩潰
                do 
                {
                    iter2--;
                    iter = s.insert(iter, *iter2);
                } while (iter2>newVal.begin());
            }
            iter += newVal.size();
        }
        else iter++;
    }
}

void replacestring(string&s, const string &oldVal, const string &newVal)//直接利用標準庫裏面的函數操作字符串極大地簡化了string的操作
{
    int p = 0;
    while ((p=s.find(oldVal,p))!=string::npos)
    {
        s.replace(p, oldVal.size(), newVal);
        p += newVal.size();
    }
}


void name_string(string&name, const string &prefix, const string &suffix)//利用迭代器來進行插入和尾增操作
{
    name.insert(name.begin(), 1, ' ');
    name.insert(name.begin(), prefix.begin(), prefix.end());
    name.append(" ");
    name.append(suffix.begin(), suffix.end());
}
void namestring(string &name, const string&prefix, const string &suffix)//按長度和位置進行string管理
{
    name.insert(0, " ");
    name.insert(0, prefix);
    name.insert(name.size(), " ");
    name.insert(name.size(), suffix);

}
void find_char(string&s, const string&chars)//直接利用find_first_of(s,chars)函數進行查找返回值爲一個string::npos的特殊值，有返回字符串，沒有返回npos
{
    cout << "在" << s << "中查找" << chars << "中字符" << endl;
    string::size_type pos = 0;
    while ((pos = s.find_first_of(chars,pos))!=string::npos)
    {
        cout << "pos: " << pos<<",char: " << s[pos] << endl;
        pos++;
    }
}

void find_not_char(string&s, const string&chars)//直接利用find_first_of(s,chars)函數進行查找返回值爲一個string::npos的特殊值，有返回字符串，沒有返回npos
{
    cout << "在" << s << "中查找不在" << chars << "中字符" << endl;
    string::size_type pos = 0;
    while ((pos = s.find_first_not_of(chars, pos)) != string::npos)
    {
        cout << "pos: " << pos << ",char: " << s[pos] << endl;
        pos++;
    }
}
float SumStringInt(const vector<string> &sub)//無限整數相加，不牽扯整數大小可以是stoi(string)到int,也可以是stof(string)是float
{
    auto sum=0;
    for (auto iter = sub.begin(); iter != sub.end(); iter++)
        sum += stof(*iter);
    return sum;
}


int main(int argc, char **argv)
{

    string s = "tho thru  tho !";
    //replacestring(s, "thru", "through");
    //replace_string(s, "thru", "through");
    name_string(s, "nihao", "wobuhao");
    cout << s << endl;
    string p = "123sdv546dbjy64vs4";
    find_char(p, "1234567890");
    find_not_char(p, "1234567890");
    vector<string>sumint{"12","3456","+102","-129","+12"};
    cout << SumStringInt(sumint)<<endl;
    system("pause");
    return 0;
}

測試效果如下