c_c++_io之File

#include <iostream>
#include <fstream>

using namespace std;
void createFile(){
    fstream fs("cplus.txt",ios::trunc);

}
void writeFile(){
    ofstream of("cplus.txt",ios::app);
    of<<"hello.txt"<<endl;
    of.close();

}
void readFile(){
     fstream fin("cplus.txt",ios::in);
     char *buffer;
     //char buffer[22]?;这样才行？
     //cout<<buffer<<endl;
     fin.getline(buffer,10);
     //cout<<"error"<<endl;
     if(fin.eof()){
        cout<<"error"<<endl;
     }
     fin.close();
    //

}
int main(){
        // createFile();
         //writeFile();
         readFile();


}



 必须用gcc 编译，不能用g++,否则出错

#include <stdio.h>

#include <stdlib.h>


void createFile(char* const fileName){

    //fileName="hello";

    FILE *file=fopen(fileName,"w+");   //创建一个可读写的文件

    fclose(file);

}

char *read(char *fileName,int length){


      char *readString;

      FILE *file;

      char *p;

      file=fopen(fileName,"r");

      p=fgets(readString,length,file);

      printf("str%s\n",p);  //

      printf("readString%s\n",readString);//跟上一句效果一样

      fclose(file);


      return "hello";



}

void write(const char* fileName,char * const writeString){

      FILE *file;

      file=fopen(fileName,"w");

      fputs(writeString,file);

      fclose(file);


}

char *test2(char *p){

    char *a=p;

    return a;

}

int *test(){

    int *p;

    int a=12;

    p=&a;

    return p;

}

int main(){

   // createFile("hello2.txt");

   // write("hello2.txt","大家好");



     char *p=read("hello2.txt",22);

		printf("读取到得数是%s\n",p);


}