I'm trying to strcpy two cstring arrays into one. When I output my name it gives me this "╠".

[Blantron]

//final review
//====================================================

#include <iostream>
#include <cstring>
using namespace std;

//=====================================================

void displayInfo(char fullName[20], int & age);

int main()
{
int age;

char firstName[10] = "Allen";
char lastName[10];
char fullName[20];

cout << "Enter your age: " << endl;
cin >> age;
cout << "Enter your last name: " << endl;
cin.getline(lastName, 10);
cin.ignore();

strcpy(fullName, firstName); //<-----I'm pretty sure this is where my mistake is.
strcpy(fullName, " "); //
strcpy(fullName, lastName);

displayInfo(fullName, age);

return 0;
}

//====================================================

void displayInfo(char fullName[20], int & age)
{
cout << "Hello " << fullName[20] << ". ";
cout << "You are " << age << " years old. " << endl;
}

/*output:
Enter your age:
27
Enter your last name:
McGowan
Hello ╠. You are 27 years old.
Press any key to continue . . .*/

[Raezzor]

I think what you want is to append not copy. I'm not sure, but if I remember correctly copy will overwrite any previous value. You could use simply concatenation I believe, like this:

fullName = firstName + " " + lastName;

The reason you are getting the funky output for name though is that you are using fullname[20] as your output. Since you fullName array is declared as having size 20, it has elements from 0 to 19. 20 is outside the array. Also, remember that the array is an array of characters, so trying to output a single element of the array will only display a single character. To output the entire array simply use fullName.

Edit: Actually, <cstring> has a function called strcat that should work for you too.

http://www.cplusplus.com/reference/cstring/strcat/

All you have to do is pass the name of the destination array, then the name of the string to be added. For you that call would look like:

strcat(fullName, firstName);
strcat(fullName, " ");
strcat(fullName, lastName);

[Blantron]

Thank you so much:)

[Disch]

Note that if you strcat, you must make sure the destination string (fullName) is initialized or you may overstep array bounds.

I recommend first doing a strcpy, followed by strcats:

strcpy(fullName, firstName);  // <- strcpy first
strcat(fullName, " ");  // <- then strcat
strcat(fullName, lastName);

Of course this is much much easier and safer if you just use strings instead of char arrays... but this looks like a homework problem and I'm assuming you're not allowed to use strings.

[Blantron]

I used this code and it crashed after inputting the data, I changed what you told me to, maybe I put it in the wrong order:/
//final review
//====================================================

#include <iostream>
#include <string>
#include <cstring>
using namespace std;

//=====================================================

void displayInfo(char fullName[20], int & age);

int main()
{
int age;

char firstName[10] = "Allen";
char lastName[10];
char fullName[20];

cout << "Enter your age: " << endl;
cin >> age;
cout << "Enter your last name: " << endl;
cin.getline(lastName, 10);
cin.ignore();

strcat(fullName, firstName);
strcat(fullName, " ");
strcat(fullName, lastName);

displayInfo(fullName, age);

return 0;
}

//====================================================

void displayInfo(char fullName[20], int & age)
{
cout << "Hello " << fullName << ". ";
cout << "You are " << age << " years old. " << endl;
}

When I used strcpy the program ran but it output nothing, and this was after changing fullName in the displayInfo function.

[Raezzor]

Ah yup, Disch was right. Destination string should be initialized before you pass it to strcat. His method works well to using copy then cat.

[Blantron]

strcpy(fullName, firstName);
strcat(fullName, " ");
strcat(fullName, lastName);

This only gives me the first name, I've tried several variations but I can't get the last name to output. The space outputs as well, but not the lastName array.

[Disch]

Works for me:

#include <iostream>
#include <cstring>
using namespace std;

int main()
{
    char firstname[] = "John";
    char lastname[] = "Doe";
    char fullname[20];

    strcpy(fullname,firstname);
    strcat(fullname," ");
    strcat(fullname,lastname);

    cout << fullname; // outputs "John Doe" as expected
}

Make sure your 'lastName' array actually contains a name and isn't empty.


EDIT: ah, yes... that's the culprit:

cin >> age;  // using the >> operator leaves the newline in the buffer
cout << "Enter your last name: " << endl;
cin.getline(lastName, 10);  // so this returns immediately with an empty string
cin.ignore();

This is one of the many reasons I hate using iostream. It's super confusing and filled with these kinds of gotchas. I still don't fully understand how it all works. Anyway, you might be able to fix this by moving the ignore() call so it's ABOVE the getline(lastName call.

[Blantron]

SUCCESS!! That was the problem sir:) Thanks a million!