c++对文件操作的支持(二)

#include <stdio.h>
#include <iostream>
#include <fstream>
using namespace std;
void main()
{       
    int a,b;
    char c;
    ofstream fout("test.txt");
    fout<<0<<" "<<1<<" "<<4<<endl;
    fout<<3<<" "<<4<<" "<<'d'<<endl;
    ifstream fin("test.txt");
    while (!fin.eof())
    {
        fin>>a>>b>>c;
        if(fin.fail()) continue;    //忽略文件中的空行
        cout<<a<<" "<<b<<" "<<c<<endl;
    }
    cin>>a;
}

 

http://www.cplusplus.com/doc/tutorial/files/">http://www.cplusplus.com/doc/tutorial/files/

2.

#include <iostream>
#include <fstream>
using namespace std;

char *getmemory ()
{
    char *p = (char *)malloc(100*sizeof(char));
    return p;
}

void getmemory2(char**p)
{
    *p = (char *)malloc(100*sizeof(char));
}

int main()
{
    static int num =0;
    char *str = NULL;
    //知识点1___给str分配内存的几种方法
    //str= getmemory();
    //getmemory2(&str);
    //str = (char*)malloc(100*sizeof(char));
    str = (char *) calloc(100,sizeof(char));  //区别与malloc： calloc在动态分配完内存后，自动初始化该内存空间为零，而malloc不初始化，里边数据是随机的垃圾数据
    //str = new char[100];
    memset(str,0,100);    //    初始化  ； 赋值语句 = strcpy(str,"sadfsa");

    double a = 0.0;    
    int b = 0;
    char c='a';
    ifstream fin("data.txt");
    while (!fin.eof())
    {
        fin.getline(str,1000);
        if (strlen(str) ==0) continue;        //知识点2___对文件中出现空行的处理
        sscanf(str,"%lf,%d,%c",&a , &b ,&c);    //知识点3___将读取的字符串转换为相应的数据类型
        num++;
        if (num ==1)
            cout<<"data.txt中的数据如下"<<endl;
        cout<<a<<","<<b<<","<<c<<endl;
    }
    free(str);
    cout<<"文件共有"<<num<<"数据"<<endl;
    return 0;
}

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