c与c++之间的转换以及流的运用

#include"aa.h"

#include<iostream>

#include<stdio.h>

#include<string.h>

#include<fstream>

#include<sstream>

#include<iomanip>

#include<string>

using namespace std;

int main()

{ 
//c语言的字符串转化为c++字符串
char *i="abc";
char j[4]="def";
string k1=i;
string k2=j;
cout<<i<<endl;
//c++的字符串转化为c语言字符串

const char *i2=k1.c_str();

cout<<i2<<endl;
//c语言转换“1.1”为1.1
string  a="1.1";
float cc;
cc=atof(a.c_str());
cout<<cc<<endl;
//c++用流的形式
string a1="1.2";
stringstream str(a1),str2;
float bb;
str>>bb;
cout<<bb<<endl;
//double转化为string
string i1;
stringstream jj(i);
double source=3.1415926535;
jj<<setiosflags(ios::fixed)<<setprecision(3)<<source ;//头文件iomanip
jj>>i1;

cout<<i1<<endl;

return 0;

}