fread将数据读入CString型变量问题

[halolodudu]

void main()
{
	FILE* fr = NULL;
	fr = fopen("C:\\Users\\jokebibi\\Desktop\\TxtRead.txt","rb");
	CString Buff;
	if(fr)
	{
		fseek(fr,25,SEEK_SET);
		fread(&Buff,1,13,fr);
		fclose(fr);
	}
	FILE* fw = NULL;
	fw = fopen("C:\\Users\\jokebibi\\Desktop\\TxtWrite.txt","wb");
	if(fw)
	{
		CString Temp;
		Temp = "[SPVersion]\r\n";
		fwrite(&Temp,1,13,fw);
		fwrite(&Buff,1,13,fw);
		LPTSTR m_lpFilePath = "ZJ_HT_JPR.exe";
		m_lpszImageName = m_lpFilePath;
		LPVOID m_lpResult;
		m_lpResult = GetVersionDemo();
		printf("%s",m_lpResult);
		fwrite(m_lpResult,1,10,fw);
		fclose(fw);
	}
	
}

单步调试发现，Buff中没有数据写入，并且在fclose（fr）时报错，请教各位是哪里出现问题了？

[笨笨仔]

你这程序在读文件时为何不监视返回值？从返回值即可判定原因。

[笨笨仔]

你这程序为何不判断文件读、写的返回值？返回值会告诉你操作结果！

[赵4老师]

仅供参考：

#include <sys\stat.h>
#include <io.h>
#include <fcntl.h>
#include <share.h>
#include <stdlib.h>
#include <stdio.h>
#include <conio.h>
#include <string.h>
#define MAX_CLU_BYTES 65536
FILE *fo;
int fh;
__int64 offs,offs1;
__int64 rvi64;
int rv,wrv;
unsigned char buf[MAX_CLU_BYTES];
char ofn[_MAX_PATH];
char offstr[80];
char drive[_MAX_DRIVE];
char dir[_MAX_DIR];
char fname[_MAX_FNAME];
char ext[_MAX_EXT];
char fullpath[_MAX_PATH];
void strcpybutcomma(char *t,char *s) {
    char c;

    while (1) {
        c = *s++;
        if (','!=c) *t++ = c;
        if (0==c) break;
    }
}
int main(int argc,char **argv) {
    if (argc<3) {
        printf("Copy File Tail.\n");
        printf("Usage:\n");
        printf("    cft filename.ext {Offset_Begin|-Offset_End|Offset_Begin-Offset_End}\n");
        printf("Copy filename.ext {OB|-OE|OB-OE} to {OB|~OE|OB-OE}-filename.ext\n");
        printf("Note: Byte at OE is NOT included.\n");
        printf("Example:\n");
        printf("    cft abc.rar 12345\n");
        printf("Copy abc.rar offset 12345-end to 12345-abc.rar\n");
        printf("    cft abc.rar -12345\n");
        printf("Copy abc.rar offset -12345-end to ~12345-abc.rar\n");
        printf("    cft abc.rar 123-12345\n");
        printf("Copy abc.rar offset 123-12345 to 123-12345-abc.rar\n");
        printf("    cft abc.rar 0xAB-0xCD\n");
        printf("Copy abc.rar offset 0xAB-0xCD to 0xAB-0xCD-abc.rar\n");
        return 1;
    }
    strcpybutcomma(offstr,argv[2]);
    rv=sscanf(offstr,"%I64i-%I64i",&offs,&offs1);
    if (rv==0) {
        printf("offset %s is not number\n",argv[2]);
        return 2;
    }
    if (NULL==_fullpath(fullpath,argv[1],_MAX_PATH)) {
        printf("Can not get fullpath of %s\n",argv[1]);
        return 10;
    }
    fh=_sopen(fullpath,_O_BINARY|_O_RDONLY|_O_RANDOM,_SH_DENYNO);
    if (fh==-1) {
        printf("_sopen %s errno=%d %s\n",fullpath,errno,strerror(errno));
        return 3;
    }
    if (rv==1) {
        offs1=_filelengthi64(fh);
        if (offs1==-1i64) {
            printf("%I64d=_filelengthi64 errno=%d %s\n",offs1,errno,strerror(errno));
            _close(fh);
            return 4;
        }
        if (offs<0i64) {
            offs=offs1+offs;
            if (offs<0i64) offs=0i64;
        }
    } else {//rv==2
        if (offs>offs1) {
            printf("%s offset_begin %I64d > %I64d offset_end error\n",argv[2],offs,offs1);
            _close(fh);
            return 5;
        }
    }
    rvi64=_lseeki64(fh,offs,SEEK_SET);
    if (rvi64!=offs) {
        printf("%I64d=_lseeki64 %I64d errno=%d %s\n",rvi64,offs,errno,strerror(errno));
        _close(fh);
        return 6;
    }
    _splitpath(fullpath,drive,dir,fname,ext);
    if (offstr[0]=='-') offstr[0]='~';
    sprintf(ofn,"%s%s%s-%s%s",drive,dir,offstr,fname,ext);
    fo=fopen(ofn,"wb");
    if (fo==NULL) {
        printf("fopen %s errno=%d %s\n",ofn,errno,strerror(errno));
        _close(fh);
        return 7;
    }
    cprintf("\n%I64d\r",offs);
    while (1) {
        rv=_read(fh,buf,(unsigned int)__min(offs1-offs,MAX_CLU_BYTES));
        if (rv==0) break;//
        if (rv<0) {
            printf("_read %s offset %I64d errno=%d %s\n",fullpath,offs,errno,strerror(errno));
            fclose(fo);
            _close(fh);
            return 8;
        }
        wrv=fwrite(buf,1,rv,fo);
        if (wrv!=rv) {
            printf("fwrite %s errno=%d %s\n",ofn,errno,strerror(errno));
            fclose(fo);
            _close(fh);
            return 9;
        } else {
            offs+=rv;
            cprintf("%I64d\r",offs);
            if (offs>=offs1) break;//
        }
    }
    fclose(fo);
    _close(fh);
    printf("Copy %s offset %s to %s OK.\n",fullpath,argv[2],ofn);
    return 0;
}

[Eleven]

读取文件到char[],然后转换成CString类型。

[lx624909677]

Temp是CString类型的变量，CString是一个类，里面除了字符串还有很多其他信息，肯定不能直接用这个类型来接收数据，而是应该用一个字符数组来接收后，再赋值给CString

[蒋晟]

fread获得的是二进制数据 要转成字符串的话要解码，这需要预知或者猜测文件编码 比如big5的曹操你拿gb2312来解码就成了变巨