two strcpy-ies crashes my program

Hi.

I have a strange problem with the following code. It compiles without errors, but when i start it, it crashes when the second strcpy-command should be done. When I delete one strcpy-command (no matter which one) it works without problems. Why can't I use two strcpys in one code here?

Code:

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#include<iostream>
using namespace std;

int main()
{
    char *stra[10];
    char *strb[10];
   
    strcpy(*stra, "hallo");
    strcpy(*strb, "hallo");
    return(0);
}

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Quote:

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Originally Posted by Jakob

When I delete one strcpy-command (no matter which one) it works without problems.

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Does it really works? I don't thinks so. Anyway maybe you need this:

Code:

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#include <iostream>
#include <cstring>


using namespace std;

int main()
{
    char stra[10];
    char strb[10];
   
    strcpy(stra, "hallo");
    strcpy(strb, "hallo");
   
    return(0);
}

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With this line

Code:

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char *stra[10];

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you defined array of 10 pointers to type char.
If your intetnion was to do this then you must first allocate memory otherwise you'll get a seg. fault
So correct version would be:

Code:

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char *stra[10];
stra[0] = new char[10]; //allocate enough memory to store 10 character
 strcpy(*stra, "hallo");
//or  strcpy(stra[0], "hallo");

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when using *stra that means you use stra[0] in this case.
I repeat I don't know if your intetion was to define array of pointers to type char in the first place. Did you want to define array of C strings?

> Why can't I use two strcpys in one code here?
They're both wrong, but it takes a while for programs to crash usually.

Code can simultaneously be tolerant and sensitive of programming errors, so it's not sufficient to say that it "compiles without warnings" or "runs without errors" to determine if it is bug free or not.

> strcpy(*stra, "hallo");
Which is strcpy(stra[0], "hallo");
But this doesn't point anywhere, so you just spray 6 bytes of data over some random memory location. Depending on luck, this may or may not crash your program.

Oops, thank you. I mixed up this pointer-stuff. It works without the *s. Interesting how long one can work on an easy problem like this...