Process returned -1073741819 (0xC0000005) in Code Blocks

Question

Process returned -1073741819 (0xC0000005) in Code Blocks

I have been trying to solve polynomial addition with any variable in c so I get a bug when splitting the string and assigning it to an array after assigning my code crashes with the output

Enter the number of equations :  1
Enter the 1 Equation :  6x^2+3y^2+3x^1
Substring 6x
Value 6x
i : 0 j : 0 k : 0
Substring 2
Value 2
i : 0 j : 0 k : 1
Substring 3y
Value 3y
i : 0 j : 1 k : 0
Substring 2
Value 2
i : 0 j : 1 k : 1
Substring 3x
Value 3x
i : 0 j : 2 k : 0
Substring 1
Value 1
i : 0 j : 2 k : 1

Process returned -1073741819 (0xC0000005)   execution time : 3.963 s 
Press any key to continue.

My code is

int no_of_equation;
printf("Enter the number of equations :  ");
scanf("%d",&no_of_equation);
char equation_arr[no_of_equation][59];
for (int i = 0;i < no_of_equation; i++) {
    printf("Enter the %d Equation :  ",i+1);
    scanf("%s",equation_arr[i]);
}
char *substr;
char coefficient_array[no_of_equation][10][2][6];
for (int i = 0;i < no_of_equation; i++) {
    substr = strtok(equation_arr[i],"^+");
    while(substr != NULL) {
        for(int j = 0;j < 10; j++) {
            for(int k = 0;k < 2;k++){
                strcpy(coefficient_array[i][j][k],substr);
                printf("Substring %s\n",substr);
                printf("Value %s\n",coefficient_array[i][j][k]);
                printf("i : %d j : %d k : %d\n",i,j,k);
                substr = strtok(NULL,"^+");
            }
        }
    }
}

arrays

c

string

pointers

asked on Stack Overflow Nov 6, 2020 by

Gowtham T G • edited Nov 6, 2020 by

Jem Tucker

2 Answers

for (int k = 0; k < 2; k++) {
  strcpy(coefficient_array[i][j][k], substr);      // substr may be NULL here
  printf("Substring %s\n", substr);
  printf("Value %s\n", coefficient_array[i][j][k]);
  printf("i : %d j : %d k : %d\n", i, j, k);
  substr = strtok(NULL, "^+");                     // substr may become NULL here
}

See comments above: the problem happens when you ar at the end of the string, substr becomes NULL, and in the next iteration you try to strcpy from a NULL pointer which crashes your program.

You need to put another test into the end condition of the for loop:

for (int k = 0; k < 2 && substr != NULL; k++)

I suggest you learn how to use your debugger. With a debugger this kind of simple bugs can be found in minutes.

answered on Stack Overflow Nov 6, 2020 by

Jabberwocky

There is a strong issue in your program, strtok may return NULL. And strcpy crashes if you put null in parameter.

int main ()
{
  int no_of_equation;
  printf("Enter the number of equations :  ");
  scanf("%d",&no_of_equation);
  char equation_arr[no_of_equation][59];
  for (int i = 0;i < no_of_equation; i++) {
    printf("Enter the %d Equation :  ",i+1);
    scanf("%s",equation_arr[i]);
  }
  char *substr;
  char coefficient_array[no_of_equation][10][2][6];
  for (int i = 0;i < no_of_equation; i++) {
    substr = strtok(equation_arr[i],"^+");
    while(substr != NULL) {
      for(int j = 0;j < 10; j++) {
        for(int k = 0;k < 2;k++){
          if (substr)
            strcpy(coefficient_array[i][j][k],substr);
          else
            coefficient_array[i][j][k][0] = 0;
          printf("Substring %s\n",substr);
          printf("Value %s\n",coefficient_array[i][j][k]);
          printf("i : %d j : %d k : %d\n",i,j,k);
          substr = strtok(NULL,"^+");
        }
      }
    }
  }
}

answered on Stack Overflow Nov 6, 2020 by

Robert

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