Question

#include "stdafx.h"
#include "string.h"
#include <stdlib.h>

int _tmain(int argc, _TCHAR* argv[])
{
    FILE *fp1, *fp2;
    char ime[32], prezime[32]; char brojbodova[5];
    fp1 = fopen("ulaz.txt", "r");
    char linija[100];
    char linijacopy[100];
while(fgets(linija, sizeof(linija), fp1) != NULL)
    {
/* or this: while (!feof(fp1))
        {
            fgets(linija, sizeof(linija), (FILE*)fp1);
            rest of code*/

    strcpy(linijacopy, linija);
    strcpy(ime, strtok(linija , " "));
    strcpy(prezime, strtok(NULL, " "));
    strcpy(brojbodova, strtok(NULL, " "));
    int bbodova = atoi(brojbodova);
    if(bbodova <= 50)
    {
        printf("%s\n", linijacopy);

    }

   }
fclose(fp1);
    return 0;
}

当我构建此解决方案时，我没有任何错误，但是当我运行此程序时，在打印结果后，我得到以下Windows错误：

控制台应用程序已停止工作。

Windows can check online for a solution to the problem.

And there are three options:

-Check online...

-Close the program

-Debug the program

Problem details:

Problem signature: Problem Event Name: APPCRASH
Application Name: ConsoleApplication8.exe 
Application Version: 0.0.0.0 
Application Timestamp: 5834b1c7 
Fault Module Name: MSVCR110D.dll 
Fault Module Version: 11.0.50727.1 
Fault Module Timestamp: 5011aa23 
Exception Code: c0000005 
Exception Offset: 0008f7b3 
OS Version: 6.1.7601.2.1.0.256.1 
Locale ID: 9242 
Additional Information 1: 0a9e 
Additional Information 2: 0a9e372d3b4ad19135b953a78882e789 
Additional Information 3: 0a9e 
Additional Information 4: 0a9e372d3b4ad19135b953a78882e789

此程序在VS 2012中输入，操作系统是Windows 7 32 Enterprise。

Answer 1

你的问题是假设每个函数都返回有效的指针，这是错误的

您必须检查fopen()的返回值，否则您将取消引用NULL指针。
您必须检查strtok()的返回值，同样的问题→NULL指针取消引用。

Answer 2

以下代码解决了问题注释中列出的所有问题，并通过消除不需要的变量，代码逻辑等大大简化了代码。

//#include "stdafx.h"
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#define MAX_LINE_LEN (100)

int main( void )
{
    FILE *fp1 = NULL;
    char *brojbodova;

    if( NULL == (fp1 = fopen("ulaz.txt", "r") ) )
    { // fopen failed
        perror( "fopen for ulaz.txt failed" );
        exit( EXIT_FAILURE );
    }

    // implied else, fopen successful

    char linija[ MAX_LINE_LEN ];
    char linijacopy[ MAX_LINE_LEN ];

    while(fgets(linija, sizeof(linija), fp1))
    {
        strcpy(linijacopy, linija);

        if( strtok(linija , " "))
        {
            if( strtok(NULL, " "))
            {
                if( NULL != (brojbodova = strtok(NULL, " ") ) )
                {
                    int bbodova = atoi(brojbodova);
                    if(bbodova <= 50)
                    {
                        printf("%s\n", linijacopy);
                    }
                }

                else
                { // invalid line format
                    printf( "invalid line format, exiting: %s\n", linijacopy );
                }
            }

            else
            { // invalid line format
                printf( "invalid line format, exiting: %s\n", linijacopy );
            }
        }

        else
        { // invalid line format
            printf( "invalid line format, exiting: %s\n", linijacopy );
        }
   } // end while

    fclose(fp1);
} // end function: main

以上代码在我的计算机上正常运行。

由于我在本地目录中没有名为：ulaz.txt的文件，因此它会输出相应的系统消息。

输出：

fopen for ulaz.txt failed: No such file or directory

程序按预期工作，但在打印结果后，我收到错误消息

2 个答案: