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Invalid read/write of size 8 2

由 痴心易碎 提交于 2019-12-02 08:16:25

Did you try removing the newline from the last line of 'Graph.txt' and running the binary?

Also, you SHOULD do something about the leaks reported by valgrind. Check this modified code

#include<stdio.h>
#include<stdlib.h>
#include<string.h>

#define MAXFILENAME 20

typedef struct tNode{
        int Deg;
        int Val;
        int* Neigh;
} *tNodePtr;

typedef struct tGraph{
        int Num;
        tNodePtr* Nodes;
} *tGraphPtr;


void GInit(tGraphPtr G, const char *FNum)
{
        char FileName[MAXFILENAME];
        char *FileNamePrefix = "Graph";
        char *FileNamePostfix = ".txt";
        FILE *FilePtr;
        int FileBrowser;
        int i, j, k, countNeigh;
        char *line;
        char c;

        strcpy(FileName, FileNamePrefix);
        strcat(FileName, FNum);
        strcat(FileName, FileNamePostfix);

        FilePtr = fopen(FileName, "r");

        if(!FilePtr)
                printf("Can't open file \"%s\"\n", FileName);
        else
        {
                if(!fscanf(FilePtr, "%d", &FileBrowser))
                        printf("fscanf error 1!\n");

                G->Num = FileBrowser;
                G->Nodes = calloc(G->Num , sizeof *(G->Nodes));
                if(G->Nodes == NULL)
                {
                        printf("Memory allocation error 1!\n");
                        return;
                }

                for(i = 0; i < G->Num; i++)
                {
                        G->Nodes[i] = malloc(sizeof *(G->Nodes[i]));
                        if(G->Nodes[i] == NULL)
                        {
                                printf("Memory allocation error 2!\n");
                                return;
                        }
                }

                line = malloc((2*G->Num + 1) * sizeof *line );
                if(line == NULL)
                {
                        printf("Memory allocation error 3!\n");
                        return;
                }


                i = 0;
                if(!fscanf(FilePtr, "%c", &c))
                        printf("fscanf error 2!\n");
                if(fgets(line, 2*G->Num + 1, FilePtr) == NULL)
                        printf("fgets error 1!\n");
                while(!feof(FilePtr))
                {
                        countNeigh = 0;
                        j = 0;
                        while(line[j] != '\0')
                        {
                                if(line[j] == '1')
                                        countNeigh++;
                                j++;
                        }
                        G->Nodes[i]->Deg = countNeigh;
                        G->Nodes[i]->Val = i;
                        G->Nodes[i]->Neigh = malloc(countNeigh * sizeof *(G->Nodes[i]->Neigh));
                        if(G->Nodes[i]->Neigh == NULL)
                        {
                                printf("Memory allocation error 4!\n");
                                return;
                        }


                        j = 0;
                        k = 0;
                        while(line[j] != '\0')
                        {
                                if(line[j] == '1')
                                {
                                        G->Nodes[i]->Neigh[k] = j/2;
                                        k++;
                                }
                                j++;
                        }

                        i++;
                        if(fgets(line, 2*G->Num + 1, FilePtr) == NULL)
                                if(i < G->Num)
                                        printf("fgets error 2!\n");
                }

                free(line);
        }

        fclose(FilePtr);
}

void GPrint(const tGraphPtr G)
{
        int j, k;
        int i;

        printf("Graph demonstration:\n");
        for(j = 0; j < G->Num; j++)
        {
                printf("I'm Node: %d , my degree is: %d and my neighbours are:\t", G->Nodes[j]->Val, G->Nodes[j]->Deg);
                for(k = 0; k < G->Nodes[j]->Deg; k++)
                        printf("%3d", G->Nodes[j]->Neigh[k]);
                printf("\n");
        }

        for(i = 0; i < G->Num; i++)
        {
                free (G->Nodes[i]->Neigh);
                free (G->Nodes[i]);
        }

        free (G->Nodes);
}

void GDelete(tGraphPtr G)
{

}

int main(int argc, char *argv[])
{

        tGraphPtr TmpGraph;
        char *FNum;
        FNum = "1";

        TmpGraph = malloc(sizeof *TmpGraph);
        if(TmpGraph == NULL)
        {
                printf("Memory allocation error 5!\n");
                return -1;
        }

        GInit(TmpGraph, FNum);

        GPrint(TmpGraph);

        free (TmpGraph);

        return(0);
}

The o/p with valgrind

[sourav@localhost ~]$ gcc -g so_test1.c -o test
[sourav@localhost ~]$ valgrind --leak-check=full ./test 
==23941== Memcheck, a memory error detector
==23941== Copyright (C) 2002-2009, and GNU GPL'd, by Julian Seward et al.
==23941== Using Valgrind-3.5.0 and LibVEX; rerun with -h for copyright info
==23941== Command: ./test
==23941== 
Graph demonstration:
I'm Node: 0 , my degree is: 2 and my neighbours are:      1  3
I'm Node: 1 , my degree is: 4 and my neighbours are:      0  2  4  5
I'm Node: 2 , my degree is: 4 and my neighbours are:      1  3  4  5
I'm Node: 3 , my degree is: 2 and my neighbours are:      0  2
I'm Node: 4 , my degree is: 2 and my neighbours are:      1  2
I'm Node: 5 , my degree is: 2 and my neighbours are:      1  2
==23941== 
==23941== HEAP SUMMARY:
==23941==     in use at exit: 0 bytes in 0 blocks
==23941==   total heap usage: 16 allocs, 16 frees, 533 bytes allocated
==23941== 
==23941== All heap blocks were freed -- no leaks are possible
==23941== 
==23941== For counts of detected and suppressed errors, rerun with: -v
==23941== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 12 from 8)
[sourav@localhost ~]$

Well, my Graph.txt DOES NOT have a newline at the end.

标签
c
malloc
valgrind
sizeof
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