C语言把文件读入字符串以及将字符串写入文件

浅浅的花香味﹌ 2021-07-04 23:02 725阅读 0赞

## 1.纯C实现 ##

FILE *fp;
    	if ((fp = fopen("example.txt", "rb")) == NULL)
    	{ 
    		exit(0);
    	}
    	fseek(fp, 0, SEEK_END);
    	int fileLen = ftell(fp);
    	char *tmp = (char *) malloc(sizeof(char) * fileLen);
    	fseek(fp, 0, SEEK_SET);
    	fread(tmp, fileLen, sizeof(char), fp);
    	fclose(fp);
    	for(int i = 0; i < fileLen; ++i)
    	{ 
    		printf("%d ", tmp[i]);
    	}
    	printf("\n");
     
    	if ((fp = fopen("example.txt", "wb")) == NULL)
    	{ 
    		exit(0);
    	}
    	rewind(fp);
    	fwrite(tmp, fileLen, sizeof(char), fp);
    	fclose(fp);
    	free(tmp);

## 2.利用CFile（MFC基类） ##

`CFile`需要包含的头文件为`Afx.h`

打开文件的函数原型如下

if(!(fp.Open((LPCTSTR)m_strsendFilePathName,CFile::modeRead)))

有多种模式,常用的有如下:

modeRead
    
    modeWrite
    
    modeReadWrite
    
    modeCreate

文件类型有两种:

typeBinary
    
    typeText

读写非文本文件一定要用`typeBinary`

读取数据的函数原型:

virtual UINTRead(void*lpbuf, UINT nCount);

将文件读出:

CFile fp;
    if(!(fp.Open((LPCTSTR)m_strsendFilePathName,CFile::modeRead)))
    { 
        return;
    }
    fp.SeekToEnd();
    unsignedint fpLength = fp.GetLength();
    char *tmp= new char[fpLength];
    fp.SeekToBegin();    //这一句必不可少
    if(fp.Read(tmp,fpLength) < 1)
    { 
        fp.Close();
        return;
    }
    
    // 新建文件并写入
    
    if(!(fp.Open((LPCTSTR)m_strsendFilePathName, CFile::modeCreate | CFile::modeWrite |CFile::typeBinary)))
    { 
        return;
    }
    fp.SeekToBegin();
    fp.write(tmp,fpLength);
    fp.close;