进程在代码块中返回了-10737418190xC0000005

问题描述

我一直在尝试使用c中的任何变量来解决多项式加法，因此在拆分 字符串，并在分配我的代码后将其分配给数组，并使其输出

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.

我的代码是

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,"^+");
            }
        }
    }
}

解决方法

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
}

请参见上面的注释：当您在字符串末尾substr变为NULL，并且在下一次迭代中，您尝试从NULL指针进行strcpy崩溃时，就会发生此问题。

您需要在for循环的结束条件中进行另一个测试：

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

我建议您学习如何使用调试器。使用调试器，可以在几分钟内找到这种简单的错误。

,

程序中存在一个严重问题，strtok可能返回NULL。 如果在参数中输入null，则strcpy会崩溃。

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",k);
          substr = strtok(NULL,"^+");
        }
      }
    }
  }
}