c++ by using argc and argv read the text file -

////////// new update!!!!! ////////// 

.txt have 15 numbers , last number "15" 1. try count how many(save index) of numbers in .txt file. 2. create dynamic array size index. 3. save number dynamic array.

question: how cover char dynamic array int dynamic array.

i got garbage output in terminal:

open sucessues!!   index: 15 buffer: 15 0 1073741824 0 1073741824 2136670223 32767 -1680479188 32767 0 0 0 0 0 0 0  int main(int argc, char* argv[]) {  char *nptr = argv[1]; char *buffer = new char[5]; int index = 0;    ifstream fin(nptr); //open file if (argc > 1){  // allocate memory if(!fin){  cout << "can't read file!!" << endl;   return -1; }  if(fin){      cout << "open sucessues!! " << endl; }     while (!fin.eof()){  fin >> buffer; index++; //counting here!!! }  cout << "index: " << index << endl; //print out counting results! cout << "buffer: " << buffer << endl; // checking last number!  should "15"  delete[] buffer; //  buffer = null;  int *number = new int[index];  char *temp = new char[index]; int *home = number; //home  while(!fin.eof()){      fin >> temp;     *number= atoi(temp); //im confessing right here!!!     number++;     temp++; }    number = home;  (int = 0; < index; ++i) {     cout << *number << endl;  //*number print out garbage， don't know why!     number++; }     fin.close( ); }  return 0; } /////************ 

//////// old ///////// don't read /////i wondering how use argc , argv read file: numbers.txt(few numbers inside). goal is: read file ./sort in terminal like: ./sort numbers use buffer , index count how many number inside, use index create dynamic array, read file again, change "number" int using atoi.

i got segmentation fault: 11 after type: ./sort numbers in terminal.

can me here? need array sort number. here got far:

int main(int argc, char* argv[]) {      char *nptr = argv[1];      char *buffer[3];     int index = 0;       ifstream fin(nptr); //open file       // allocate memory     if(fin.is_open()){       cout << "open" << endl;              while(!fin.eof()){                 fin >> *buffer;                 index++;                }      cout << index << endl;     } 

char *buffer[3]; 

creates array of 3 pointers characters. not allocate storage point at. not assign storage pointed at. these pointer pointing @ anything. valid memory, invalid memory, older brother's porn stash, don't know. if lucky, point invalid memory , program crash.

fin >> *buffer; 

attempts place string read file memory pointed @ first of 3 pointers above. since don't know point, don't know input file written. odds pretty try write invalid memory , program crash.

to solve this, allocate storage, point pointer @ storage, , read pointer.

eg.

char *buffer[3]; char storage[128]; buffer[0] = storage; 

then later

fin >> *buffer; 

that said, don't think want @ all. more

char *buffer[3]; 

should

char buffer[3]; 

in case

fin >> *buffer; 

will read 1 character file buffer, that's typo ,

fin >> buffer; 

is intended. warning!!! still crash if string read fin longer 2 characters. want rethink in general.

if allowed use std::string , std::vector, seeing still in semester instructor expects teach code having hit things rocks , maybe rub twigs produce fire.