arrays - C program that reads from file or stdin and removes blank lines -


i new c , here have c program take in x amount of files command line , output files stdout deletes blank lines. if user doesn't input files read directly stdin.

everything functions smoothly except removing of lines.

here program

#include <stdio.h> #include <stdlib.h> #include <string.h> #include <ctype.h> #define numchars 1024   int main (int argc, char** argv)  {     int good_file = 0;      if(argc <= 1){         good_file++;         test(stdin);     }      file* files[argc - 1];     int i;     for(i = 0; < argc - 1; i++){         if ((files[i]=fopen(argv[i+1], "r"))==null){             continue;             }                 else{                     good_file++;                     test(files[i]);             }      }          if(!good_file){             fprintf(stderr, "error!\n");         }  }  int test (file *file)     {         char buffer[numchars];          while (fgets(buffer, numchars, file) != null)                 part2(buffer);             fclose(file);      }  int part2 (char *buffer) {     if(*buffer != '\n' || *buffer != '\t' || *buffer != ' '){           //if(*buffer != '\n') deletes (skips) plain newlines     fputs(buffer, stdout);     } }

in function part 2, can see comment program delete (skips) just newlines if remove || '\t' , ' ' in if statement. lot of blank lines not "blank". i.e have tabs or white space on them. using logic had removing newlines applied tabs , white space well.

but new implementation won't skip newlines. , doesn't work ever.

appreciate feedback!

your condition here true, precisely nothing:

if (*buffer != '\n' || *buffer != '\t' || *buffer != ' ') {     fputs(buffer, stdout); }

you're asking "is first character not newline or not tab or not space?" every character can that: space not newline, , newline not tab. need check characters in line:

int is_all_white(char *s) {     while (*s) {         if (!('\n' == *s || '\t' == *s || ' ' == *s)) return 0;         s += 1;     }     return 1; }  ...   if (! is_all_white(buffer)) {     fputs(buffer, stdout); }

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