Thread: Overide for loop condition

Is it possible to overide a for loop condition?

I need to enter this for loop for(index = optind; index < argc; index++){: and use stdin

Code:

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

int main(int argc, char *argv[]){
  int optchar;
  int index;
  FILE *fp;
  int lineCount = 1;
  int nflag = 0;
  int sflag = 0;
  int vflag = 0;
  int tflag = 0;
  int c;
  int endline = 1;
  int newlineCount = 0;
  int cntrlFlag = 0;
  int keyboardFlag = 0;

  while((optchar = getopt (argc, argv, "nsvt")) != -1){
    switch(optchar){
      case 'n':
            nflag = 1;
        break;
      case 's':
            sflag = 1;
        break;
      case 'v':
            vflag = 1;
        break;
      case 't':
            tflag = 1;
        break;
    }
  }

  if(argv[2] == NULL){
    keyboardFlag = 1;
  }

  for(index = optind; index < argc; index++){
    if(keyboardFlag == 1){
      fp = stdin;
    }else{
      fp = fopen(argv[index], "r");
    }
      if(fp == NULL){
        fprintf(stdout,"File %s couldn't be opened!\n", argv[index]);
      }
        while((c = fgetc(fp)) != EOF){
          cntrlFlag = 0;
          if(c != '\n'){
            newlineCount = 0;
          }
          if(nflag && endline){
            if(sflag && newlineCount < 2){
              printf("%5d  ", lineCount);
              lineCount++;
            }
            if(!sflag){
              printf("%5d  ", lineCount);
              lineCount++;
            }
            endline = 0;
          }
          if(iscntrl(c) && tflag && c != '\n'){
            c += 64;
            printf("^%c", c);
            cntrlFlag = 1;
          }
          if(newlineCount < 2 && sflag && !cntrlFlag){
            printf("%c", c);
          }
          if(!sflag && !cntrlFlag){
            printf("%c", c);
          }
          if(c == '\n'){
            endline = 1;
            newlineCount++;
          }
        }
    fclose(fp);
  }
  return 0;
}

You can reset index inside the loop as much or to whatever you want.

Yes, you can. Be careful doing that however, as it can often lead to unclear, messy code. If you find that becoming a necessity, it's a good sign you might need to refactor your code or something (kind of like with goto).

In any case, like Dino, I'm not sure what you mean by override. Some other possibility are statements like continue (which terminates execution of the current iteration and restarts the loop in the next iterationg) and break which breaks outside of the current loop.