雙重釋放或腐敗（上一個！）

Question

運行C程序時，我得到了以下錯誤：*錯誤的`./final「：雙重釋放或腐敗（！上一頁）：0x0000000000c2f010 *

我相信這是由於免費（）在 程序結束時被調用，但我無法弄清楚malloc的內存在此之前被釋放的位置爲 。下面是代碼：

#include <stdio.h> 
#include <stdlib.h> 
#include<math.h> 
#include <time.h> 
#include <stdlib.h> 

static int DIM = 1000; // Golbal variable for Matrices Dimentions 
int isPrime(unsigned int number); 
int countPrimes(int **matrix); 

int main() { 

    time_t tic = clock(); 
    int **matrixA;// 
    int **matrixB; 
    int **mult; 
    int k = 0, sum=0; 
    time_t t; 
    int i =0,j; 

    // Allocate dynamic memory for Matrices A,B && mult first (rows) dimension 
    matrixA = (int **) malloc (DIM * sizeof (int *)); 
    matrixB = (int **) malloc (DIM * sizeof (int *)); 
    mult = (int **) malloc (DIM * sizeof (int *)); 
    // Allocate dynamic memory for Matrices A,B && mult second (rows) dimension, && Initialize elements to "0" For Matrices B && Mult 
    for (k = 0; k < DIM; k++) { 
     matrixA[k] = (int *) calloc (DIM, sizeof (int *)); 
     matrixB[k] = (int *) calloc (DIM, sizeof (int *)); 
     mult[k] = (int *) calloc (DIM, sizeof (int *)); 
    } 

    // Generate random numbers for matrix A elements 
    for (i = 0; i < DIM; i++) 
    { 
     for (j = 0; j < DIM; j++) 
     { 
      matrixA[i][j] = (rand() % 100)+1 ; 
      printf("%d ",matrixA[i][j]); 
     } 
    } 

    // Do the matrix multiplication 
    for (i = 0; i < DIM; i++) { 
     for (j = 0; j < DIM; j++) { 
      for (k = 0; k < j; k++) { 
       sum += matrixA[i][k] * matrixB[k][j]; 
      } 
      mult[i][j] = sum; 
     sum = 0; 
     } 
    } 

    int total = countPrimes(matrixA); 
    printf("\n\nnumber of primes in a : %d\n\n", total); 

    // Delete the dynamic memory of Matrix A 
    for (i = 0; i < DIM; i++) {   // free first matrix 
     free(*(matrixA+i)); 
    } 
    free(matrixA); 

    // Delete the dynamic memory of Matrix B 
    for (i = 0; i < DIM; i++) {   // free first matrix 
     free(*(matrixB+i)); 
    } 
    free(matrixA); 

    // Delete the dynamic memory of Matrix B 
    for (i = 0; i < DIM; i++) {   // free first matrix 
     free(*(matrixB+i)); 
    } 
    free(matrixA); 


    // Compute SpeedUp 
    time_t toc = clock(); 
    double time = (double) (toc - tic)/CLOCKS_PER_SEC; 
    printf("The amount of time the OS has spent running your process is : %lf seconds\n\n\n", time); 

    return 0; 
} 

// Check elements of Matrix A if its a Prime number or not 
int isPrime(unsigned int number) { // Psitive numbers could be Prime numbers only 
    if (number <= 1) return 0; // zero and one are not prime 
    unsigned int i; 
    for (i=2; i*i<=number; i++) { 
     if (number % i == 0) return 0; 
    } 
    return 1; 
    } 

// Count number of prime numbers in Matrix A 
int countPrimes(int **matrix) { 
    int row, col; 
    int flag = 0; 
    int total = 0; 
    for (row = 0; row < DIM; row++) { 
     for (col = 0; col < DIM; col++) { 
      flag = isPrime(matrix[row][col]); 
      if(flag == 1) 
       total++; 
     } 
    } 
    return total; 
} 

Answer 1

你的錯誤是在這裏：

// Delete the dynamic memory of Matrix A 
    for (i = 0; i < DIM; i++) {   // free first matrix 
     free(*(matrixA+i)); 
    } 
    free(matrixA); 

    // Delete the dynamic memory of Matrix B 
    for (i = 0; i < DIM; i++) {   // free first matrix 
     free(*(matrixB+i)); 
    } 
    free(matrixA); 

    // Delete the dynamic memory of Matrix B 
    for (i = 0; i < DIM; i++) {   // free first matrix 
     free(*(matrixB+i)); 
    } 
    free(matrixA); 

請注意，您free(matrixA)三次，即使你打算釋放matrixB和matrixC。您也錯誤地在兩個不同的循環中使用free(*(matrixB+i));。