1、cerr

freopen   cout输出到文件内时，cerr能输出到控制台显示

2、cin.getline()

defalut  ->  '\n'

#define IOS ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#include<bits/stdc++.h>
using namespace std;
int main(){
    //IOS;
    //freopen("a.txt","r",stdin);

    char a[1000];
    while(cin.getline(a,23333,',')){
        cout<<a<<endl;
    }




    return 0;
}

输出：
123,124,124,124,
123
124
124
124

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3、cin.peek()提前读入一个字符，但不从输入流中去掉

#define IOS ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#include<bits/stdc++.h>
using namespace std;
int main(){
    //IOS;
    //freopen("a.txt","r",stdin);

    ;
    if(isdigit(cin.peek())){
        int a;
        cin>>a;
        cout<<a<<endl;
    }
    else{
        char a[10];
        cin>>a;
        cout<<a<<endl;;
    }




    return 0;
}

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 4、cin.petback('c')将字符放回输入流前面

5、cin.ignore(ncount,delim  = 'eof')忽略n个字符，遇到delim结束

6、流操作算子

 

7、template<class T1,class T2 ....>

#define IOS ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#include<bits/stdc++.h>
using namespace std;
template<class T>
void Swap(T & a,T & b){
    T tmp = a;
    a = b;
    b = tmp;
}
int main(){
    int a = 1,b = 2;
    double c = 0.4,d = 12.4;
    Swap(a,b);
    Swap(c,d);
    cout<<a<<" "<<b<<endl<<c<<" "<<d<<endl;
    // Swap(b,c)报错
    return 0;
}

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 可重载

8、

#define IOS ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#include<bits/stdc++.h>
using namespace std;
template<class T1,class T2,class T3>
void Map(T1 begin,T1 end,T2 pur,T3 opt){
    for(T1 t = begin;t!=end;++t,++pur){
        *pur = opt(*t);
    }
}
int opt1(int x){
    return x*x;
}
double opt2(int x){
    return sqrt((double)x);
}
int main(){
    int a[5]  = {1,2,3,4,5};
    double b[5];int c[5];
    Map(a,a+5,c,opt1);
    Map(a,a+5,b,opt2);
    for(int i = 0;i<5;++i)cout<<b[i]<<" ";
    cout<<endl;
    for(int i = 0;i<5;++i)cout<<c[i]<<" ";
    cout<<endl;
}

输出：
1 1.41421 1.73205 2 2.23607
1 4 9 16 25

View Code

 9、类模板：略