garbage character at end of string?

Question

Hi there I'm reading a string and breaking each word and sorting it into name email and phone number. with the string joe bloggs [email protected] 12345. But once i break everything down, the individual separated variables which hold the name,email and phone number have garbage characters at the end of them. I cant figure out why.

test file

//test file
#include <iostream>
#include <string>
#include "iofunc.h"
using namespace std;
int main(){
    string str1 = "joe bloggs [email protected] 12345";

    iofunc func;
    cout<<"|-----------------------getname DEMONSTRATION------------------|\n" << endl;
    func.getName(str1);

    cout<<"the names are: " << func.glob_name << endl;

    cout<<"\n|-----------------------getphone DEMONSTRATION------------------|\n" << endl;
    func.getPhone(str1);
    cout<<"the phone number is:" << func.glob_phone << endl;

    cout<<"\n|-----------------------getemail DEMONSTRATION------------------|\n" << endl;
    func.getEmail(str1);
    cout<<"the email address is:" << func.glob_email << endl;


    return 0;
}

here's my get name function, the class is too big to scroll through:)

void iofunc::getName(string arg){
    lineProcess(arg); 
    //make sure to call this depending on what function u are using

    int name_count = 0;
    int wspace_count = 0;
    int arg_len = arg.length();
    //int char_len = 0;
    char name_temp[80];

    name_count = numberofNames(); 
    //line process was called before so this will work, 
    //make sure you call line process before using this function

    //for special, condition when there is no space in front of names
    if (special_condition == true){
        int i = 0;
        while(i < arg_len){
            name_temp[i] = arg[i];
            i++;
        }
        glob_name = string(name_temp);

    }

    if (special_condition == false){
        if (name_count == 1){
            int i = 0;
            while (arg[i] != ' '){
                name_temp[i] = arg[i];
                i++;
            }
            glob_name = string(name_temp);
        }

        //for 2 names
        if (name_count == 2){
            for (int i = 0; i < arg_len;i++){
                if (arg[i] == ' '){
                    wspace_count++;
                }
                if (wspace_count !=2){
                    name_temp[i] = arg[i];
                }
            }
            glob_name = string(name_temp);
        }
        //for 3 names
        if (name_count == 3){
            for (int i = 0; i < arg_len;i++){
                if (arg[i] == ' '){
                    wspace_count++;
                }
                if (wspace_count !=3){
                    name_temp[i] = arg[i];
                }
            }
            glob_name = string(name_temp);
        }
    }

}

basic jist of all that is, im using the function called lineProcess to figure out whether there is an email, phone and name in the argument string, And the numberofNames functions gives how many names there are so that I can act accordingly.

I had to use char name_temp to copy just the names from string so that I can extract just that and assign it to the string variable named glob_name. It copies everything i need but it gives me that garbage after each extracted string.

any idea?.

EDITED

void iofunc::getName(string arg){
    lineProcess(arg); 
    //make sure to call this depending on what function u are using

    int name_count = 0;
    int wspace_count = 0;
    int arg_len = arg.length();
    //int char_len = 0;
    char name_temp[80];
    int index_track = 0;

    name_count = numberofNames(); 
    //line process was called before so this will work, 
    //make sure you call line process before using this function

    //for special, condition when there is no space in front of names
    if (special_condition == true){
        int i = 0;
        while(i < arg_len){
            name_temp[i] = arg[i];
            index_track = i;
            i++;
        }
        name_temp[index_track+1] = '\0';
        glob_name = string(name_temp);

    }

    if (special_condition == false){
        if (name_count == 1){
            int i = 0;
            while (arg[i] != ' '){
                name_temp[i] = arg[i];
                index_track = i;
                i++;
            }
            name_temp[index_track+1] = '\0';
            glob_name = string(name_temp);
        }

        //for 2 names
        if (name_count == 2){
            for (int i = 0; i < arg_len;i++){
                if (arg[i] == ' '){
                    wspace_count++;
                }
                if (wspace_count !=2){
                    name_temp[i] = arg[i];
                    index_track = i;
                }
            }
            name_temp[index_track+1] = '\0';
            glob_name = string(name_temp);
        }
        //for 3 names
        if (name_count == 3){
            for (int i = 0; i < arg_len;i++){
                if (arg[i] == ' '){
                    wspace_count++;
                }
                if (wspace_count !=3){
                    name_temp[i] = arg[i];
                    index_track = i;
                }
            }
            name_temp[index_track+1] = '\0';
            glob_name = string(name_temp);
        }
    }

}

Answer 1

add to each new string '\0' end-of string symbol

Answer 2

Garbage characters at the end of a string could indicate that you're not null-terminating the string (ending it with a 0x00 byte). This causes the string to continue reading until the next null character, which is actually past where the string's memory ends. This could even cause a segmentation fault in some cases.

You can fix this by adding '\0' to the end of each new string you create. Note that you will have to allocate a string one byte larger now, to hold that new ending character.

Answer 3

When you do things like this:

    while(i < arg_len){ 
        name_temp[i] = arg[i]; 
        i++; 
    } 

You are copying the characters of the string to name_tmp, but not the 0 at the end which terminates the string.

Answer 4

The others have pointed you in the right direction, you aren't appropriately terminating your c strings. Declaring a char array of length 80 just points to a block of memory, it doesn't initialise the array in any way, this means that unless you /0 terminate the string you copy into it, you'll get all the crap lying around on the end up to the 80 characters.

I've not written C++ in probably 15 years so the code below may not even work but hopefully it'll give you some ideas for a more elegant and maintainable solution.

void iofunc::getName(string arg){
    lineProcess(arg); 
    //make sure to call this depending on what function u are using

    int name_count = 0;
    int wspace_count = 0;
    int arg_len = arg.length();
    //int char_len = 0;
    string name_temp;

    // Let's assemble a c-str version if the inbound arg string
    char* cstr;
    cstr = new char [arg.size()+1];
    strcpy (cstr, arg.c_str());

    name_count = numberofNames(); 
    //line process was called before so this will work, 
    //make sure you call line process before using this function

    //for special, condition when there is no space in front of names
    if (special_condition == true){
        glob_name = arg;
    }

    if (special_condition == false){
        // Assuming there's at least 1 name, which we have to otherwise the original
        // code may never set glob_name, let's use the C String function strtok
        // to tokenise our newly created c string at each " ".
        // Grab the first name.
        name_temp = string(strtok(cstr, " "));
        for (int i = 1; i < name_count; i++) {
            // Grab names 2 to name_count as required and append them to name_temp
            // We need to reinsert the space as strtok doesn't grab it.
            name_temp += " " + string(strtok(NULL, " "));
        }
        // Assign our final name to glob_name
        glob_name = name_temp;
    }

}