为什么代码包含着fread就出错?

[zansan]

#include <stdio.h>

main(int argc,char *argv[])
{
char a[5];
int ind;
FILE *infile=fopen("C:\1.txt", "r" );
ind=fread(a,1,6,infile);
printf("%d %d",a[0],ind);
int fc=fclose(infile);
return 0;
}

上述代码包含fread.可以通过编译,但运行就会出错,没输出.不知道是什么原因?难道我的机器有问题?

[starwalker]

是不是C:\1.txt不存在或者没内容？

[starwalker]

使用fopen之后应该检查infile是否为NULL
如果为NULL，就不能fread

[weiym]

C:\\1.txt

[ryfdizuo]

ind=fread(a,1,6,infile);
这句有问题吧, 数组a最大容量为5;
改为:ind=fread(a,1,5,infile);

[ryfdizuo]

属于数组越界的问题;:
size_t fread(
void *buffer,
size_t size,
size_t count,
FILE *stream
);
Parameters
buffer
Storage location for data.
size
Item size in bytes.
count
Maximum number of items to be read.
stream
Pointer to FILE structure.
Return Value
fread returns the number of full items actually read, which may be less than count if an error occurs or if the end of the file is encountered before reaching count. Use the feof or ferror function to distinguish a read error from an end-of-file condition. If size or count is 0, fread returns 0 and the buffer contents are unchanged.

Remarks
The fread function reads up to count items of size bytes from the input stream and stores them in buffer. The file pointer associated with stream (if there is one) is increased by the number of bytes actually read. If the given stream is opened in text mode, carriage return–linefeed pairs are replaced with single linefeed characters. The replacement has no effect on the file pointer or the return value. The file-pointer position is indeterminate if an error occurs. The value of a partially read item cannot be determined.

[Iluly]

典型的内存段错误:

fread(a,5,1,infile);
或者
fread(a,1,5,infile);

[zansan]

FILE *infile=fopen( "C:\1.txt ", "r " );
改为 FILE *infile=fopen( "1.txt ", "r " );
问题消失.估计我这机器上的C++不认绝对路径.