C语言把文件读入字符串以及将字符串写入文件

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;