为什么我会断言失败?

问题描述：

当我尝试使用 VC2010 调试此代码时失败:

This code fails when I try to debug it using VC2010:

char frd[32]="word-list.txt";

FILE *rd=fopen(frd,"r");
if(rd==NULL)
{
std::cout<<"Coudn't open file	"<<frd;
exit(1);
}
char readLine[100]; 
while(fgets(readLine, 100, rd) != NULL)
{     
    readLine[strlen(readLine) - 1] = ' '; 
    char *token = NULL; 
    token = strtok(readLine, " ,"); 
    insert(readLine);
}

调试结果

--------------------------- Microsoft Visual C++ 调试库-----------

--------------------------- Microsoft Visual C++ Debug Library-----------

调试断言失败！

程序:...documentsvisual studio 2010ProjectsfaDebugfa.exe文件:f:ddvctoolscrt_bldself_x86crtsrcfgets.c 行:57

Program: ...documentsvisual studio 2010ProjectsfaDebugfa.exe File: f:ddvctoolscrt_bldself_x86crtsrcfgets.c Line: 57

表达式:( str != NULL )

Expression: ( str != NULL )

有关您的程序如何导致断言失败的信息，请参阅有关断言的 Visual C++ 文档.

For information on how your program can cause an assertion failure, see the Visual C++ documentation on asserts.

(按重试调试应用程序)

(Press Retry to debug the application)

我得到的错误号是 2;

The errno I get is 2;

答

我的猜测是文件无法打开，而您仍在将其传递给 fgets.如果 fgets 为空，则您的 if(rd==NULL) 不会停止执行，它只是打印出一条消息并继续执行.

My guess is that the file is failing to open, and you're still passing it to fgets. Your if(rd==NULL) doesn't stop execution of the fgets if it's null, it just prints out a message and continues with execution.

一些非常基本的错误处理:

Some very basic errorr handling:

const char* frd = "word-list.txt";

FILE *rd=fopen(frd,"r");
if(rd==NULL) {
    std::cout<<"Coudn't open file"<<endl;
    return 1;
}

char readLine[100]; 
while(fgets(readLine, 100, rd) != NULL)
{     
    readLine[strlen(readLine) - 1] = ' '; 
    char *token = NULL; 
    token = strtok(readLine, " ,"); 
    insert(readLine);
}

为什么我会断言失败?

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