Hubert's Coding Notes

#include<iostream>
#include<cstdlib>
#include<string>
#include<cstring>
using namespace std;

int main()
{
 string s;
 char a[100];
 
 //std::istream::getline(char*,int) for char*
 cin.getline(a,100);
 cout<<a<<endl;
 
 //std::getline(istream&,string) for string
 getline(cin,s);
 cout<<s;
 return 0;
}

ofstream ios::out

ifstream ios::in

fstream ios::in | ios::out

person.h

#include<cstring>
class person
{
    private:
    char name[8];
    int phone_num;
    public:
        person(char s[]="abc",int n=0){
            strcpy(name,s);
            phone_num=n;
        }
        char *getName(){
            return name;
        }
        int getPhone()
        {
            return phone_num;
        }
};

BinaryFileOutput.cpp

#include<iostream>
#include<fstream>
#include"person.h"
using namespace std;

int main()
{
    ofstream output("test.txt",ios::binary);
    person group[3]={person("Marry",100),person("Tom",101),person("Jack",102)};
    output.write((char*)group,sizeof(group));
    return 0;
}

BinaryFileInput.cpp

#include<iostream>
#include<fstream>
#include"person.h"
using namespace std;

int main()
{
    ifstream input("test.txt",ios::binary);
    person *temp_person=new person[3];
    input.read((char*)temp_person,sizeof(person)*3);
    for(int i=0;i<3;i++)
    {
        cout<<temp_person[i].getName()<<" "<<temp_person[i].getPhone()<<endl;
    } 
    return 0;
}

#include<iostream>
#include<cstdlib>
using namespace std;
template<class T>
class foo
{
    public:
    T a,b;
};
template<class T>
class bar:public foo<T>
{
    public:
    void show()
    {
        cout<<"Son";
    }
};
int main()
{
    bar<int> k;
    k.show();
    return 0;
}

#include <algorithm>
#include <string>
using namespace std; string data = "Abc"; 
transform(data.begin(), data.end(), data.begin(), ::tolower);

OR

#include
#include

using namespace std;
string &stolower(string &s)
{
    for(int i=0;i<s.length();i++)
    {
        s[i]=tolower(s[i]);
    }
    return s;
}
int main()
{
    string s="ABC";
    cout<<stolower(s);
    return 0;
}

#include<iostream>
#include<string>

using namespace std;

int main()
{
    char a;
    while(cin.get(a)&&a!='\n')
    { 
        cout<<a;
    } 
    return 0;
}

#include<iostream>
#include<string>
#include<sstream>
using namespace std;

int main()
{ 
 stringstream ss;
 string s="456";
 int x;
 
 //string to int(or double etc...)
 ss<<s;
 ss>>x;
 cout<<x;

 //string to int using stoi 
 x = stoi(s);
 //clean up stringstream
 
 ss.str("");
 ss.clear();
 
 //int(or double etc...) to string
 x=100;
 s=to_string(x);
 cout<<s;
 
 return 0;
}

#include<iostream>
#include<string>
#include<algorithm>
using namespace std;

int main()
{ 
 string s="ab@c";
 
 //reverse and begin() end()
 reverse(s.begin(),s.end());
 cout<<s<<endl;

 //
 cout<<s.length()<<endl;
 cout<<s.empty()<<endl;
 
 //s.swap(b) swap content with string b
 cout<<(int)s.find('@')<<endl;
 cout<<(int)s.find('9')<<endl;
 
 //substr 
 cout<<s.substr(1,2)<<endl;
 cout<<s.substr(0)<<endl;
 
 //erase(delete nth element)
 cout<<s.erase(s.begin()+n);
 return 0;
}