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/*parte k axo k me da segmentation fault*//*codigo dentro do main() */switch(argc){case 3  : if(argv[1][1]=='c' && argv[1][2]=='a' && argv[1][3]=='t')                                   {                                      if(strlen(argv[2] >= 30) || strlen(argv[2]<=0) )                                        {                                           printf("Maximo de 30 caracteres\n");                                           return;                                         }                                                                          else                                        concat(argv[2]);  /*funcao externa*/                                   }break;}/*funcao concat */void concat(char *s){  FILE *fi,*fo;  char ch; fi=fopen("words.txt","r"); if (fi==NULL) {   printf("Cannot open words.txt\n");   return; }  fo=fopen("concat.txt","w");  if(fo==NULL)   {       printf("Cannot Create or open concat.txt\n");       return;   }while(ch!=EOF){ while(ch!='\n')  {   ch=fgetc(fi);   fprintf(fo,"%c",ch);  } fprintf(fo,"%s",s); fprintf(fo,"%s",'\n');}fclose(fi);fclose(fo);}