(C programming) 2 dimensional char error help. "char array[lines - 1][MAX_LEN];"

At line 45 where it says "char array[lines - 1][MAX_LEN];" my IDE gives me an error, underlining lines, that says "Expression must have a constant value. The value of variable "lines" (declared at line 10) cannot be used as a constant." How can I get my code to work? I want to use the value I found with the loop before that part, subtract 1 from it, and then I want that number value to go into my 2d array

#include<stdio.h>  #include<stdlib.h>  #include<string.h>  #include "List.h"      #define MAX_LEN 160  int main(int argc, char* argv[])  {      int lines = 0;      int x = 0;      FILE *in, *out;      char line[MAX_LEN];        //check for correct number of arguments      if (argc != 3)      {          printf("Incorrect number of arguments (needs: <input file> <output file>)\n", argv[0]);          exit(1);      }        //open files for reading      in = fopen(argv[1], "r");      out = fopen(argv[2], "w");      if (in == NULL)      {          printf("Unable to open <read from> file \n", argv[1]);          exit(1);      }      if (out == NULL)      {          printf("Unable to open <write to> file\n", argv[2]);          exit(1);      }      //counting number of lines      while (fgets(line, MAX_LEN, in) != NULL)      {          lines++;      }             // Return to start of file      rewind(in);          char array[lines - 1][MAX_LEN];      int a = -1;        // Copy strings to array      while (fgets(line, MAX_LEN, in) != NULL)      {          strcpy(array[++a], line);   // Copy from file      }        //Create new list      List end = newList();        append(end, 0);        int j;  // declare j to help transverse array        // Loop till fully iterated      for (j = 1; j < lines; j++)      {          char* temp = array[j];          int complete = 0;            //move to tail and find appropriate insertion location          moveBack(end);            // Create conditions to determine where to insert new indice          while (complete != 1 && strcmp(temp, array[get(end)]) <= 0)          {                // If at the end of the array, then insert it before the last index value and set complete codnition to true (1)              if (index(end) == 0)              {                  insertBefore(end, j);                  complete = 1;              }                // If we have not found the proper position, iterate to prev              else              {                  movePrev(end);              }          }            // If complete is not true, then insert indice after last known index          if (complete == 0)          {              insertAfter(end, j);          }      }        // Convert and save to file; Start by returning to head      moveFront(end);        // Run through list, and convert from indce value to that of string      int i;      for (i = 0; i < lines; i++)      {          fprintf(out, "%s", array[get(end)]);          moveNext(end);      }        //Close files and free memory      fclose(out);      fclose(in);      freeList(&end);        return 0;  }  

https://stackoverflow.com/questions/65516037/c-programming-2-dimensional-char-error-help-char-arraylines-1max-len December 31, 2020 at 10:46AM