pull "firstword secondword" from text file into single char array - c++

Question

I am getting a segmentation fault: core dumped error when I am reading in players file..
I am trying to add both "firstname lastname" to the player struct. I am trying to access the "0th" people and increment their name because i need both first and last, i cant simply fin >> people[i].name in a simply for loop as i do for the card value (not shown) "heart two 2" for example
// deck of cards
// below are initializations
#include <iostream>
#include <fstream>
#include <ctime>
#include <stdlib.h>
#include <string>
using namespace std;
//globals
const int maxCards = 52;
//Structs
struct card {
char suit[8];
char rank[6];
int cvalue;
char location;
};
struct player {
char name[];
int total;
card hand[];
};
//program
int main()
{
char tempfName[100];
char templName[100];
//create struct array(s)
card deck[52];
card shuffledDeck[52];
player people[4];
//set defalt values
for(int i=0;i<4;i++)
{
strcopy(people[i].name,"first last");
}
//open player names file
ifstream fin2;
string fin2Name;
//get file name from user
cout << "Enter player file name...(Players.txt)" << endl;
getline(cin,fin2Name);
fin2.open(fin2Name.c_str());
//check if Players.txt opens correctly
if(!fin2.good())
{
cout << "Error with player file!" << endl;
return 0;
}
else
{
int j =0;
//fin2 >> people[j].name; //prime file
while(fin2.good())
{
//find the length
int index =0, length=0;
while(tempfName[length] != '\0')
{
length++;
}
//now add space after first name
tempfName[length] = ' ';
length++;
while(templName[index] != '\0')
{
tempfName[length] = templName[index];
length++;
index++;
}
tempfName[length]='\0';
int counter =0;
while(templName[counter] != '\0')
{
people[0].name[counter] = templName[counter]; //testing program on "0th" people
counter++;
}
}
}
}

Answer 1

In your struct, name[] and hand[] are of undetermined size. It's hence difficult to read anything into them.
Then, once you've opened the stream, you're trying to determine the length of the unitianalized tempfName[]. This ain't no good: you're not sure it's null terminated and you'll go out of bounds ! This is the origin of your segfault.
Consider initalizing these by declaring them as:
char tempfName[100]{};
char templName[100]{};
Once this is fixed, your code still loops forever on while (fin2.good()) without reading anything, and bravely adding one whitespace to tempfName until you're out of bound.
Now suppose you'd fix all this, set a length to your name and undcomment your stream reading fin2 >> people[j].name; you'd still have a very risky situation: if the data would be longer that what you've foresseen, it would be truncated and the name wouldn't have a terminating '\0'.
Recommendation 1:
Consider using std::string instead of char[] whenever you consider storing a string. Example:
struct player {
string name = "first last" ; // initialisation value: no strcpy() needed !!
int total;
card hand[5]; // length ?
};
Recommendation 2:
Loop using your stream reading as loop condition:
while (fin2 >> people[j].name) { ///!!!
...
j++; // don't foget to increment your counter
}
However be carefull, because the >> will read one string at a time, the string ending at first whilespace (so only firstname).
If you adopt recommendation 1, it would be easy to write:
while (fin2 >> tempfName >> templName) { ///!!!
people[j++].name = tempfName + " " + templName;
}
which should perform pretty muchthe same thing that your loop, but with far less instructions and risks.
Recommendation 3:
If your number of players is fixed, define the max constant and use a for instead of a while to read your data:
const int max_player = 4;
player people[max_player];
...
for (j=0; j<max_player && (fin2 >> people[j].name); j++) // instead of the former while
If your limit of 4 was arbirary, consider using vectors. But that's another story for the moment.

Answer 2

Your struct player definition is not valid:
struct player {
char name[];
int total;
card hand[];
};
The C string fields name and hand need to have a length, e.g.
struct player {
char name[32];
int total;
card hand[32];
};
Your compiler should be giving you an error for this ("incomplete type").
Note also that since you are writing C++ code then it would be better to use std::string rather than C-style char * strings - it will be easier, more robust, and you won't be mixing C and C++ idioms.