C++ STL string pointer assignment

[sysabod]

Hi,all.
Codes first.

#include <string>
#include <iostream>
using namespace std;
int main(){
	string* str1;
	str1->reserve(113);
	if(true)
	{
		string temp("I am alive now,but soon i will be dead");
		*str1= temp;	//i guess here the problem are. 
	}
	
		cout<<str1;
}

i got a run-time error when i ran it ,and i feel weird about that.

First leat me analysis this statement *str1= temp;,it invokes the

operator = function defined(which i believe is well implemented) within the

string class and assign the data string temp refers to to the string

str1 points to . Am i right?


Thanks in advance !

[aidyszh]

I think the problem is str1->reserve(113);, because str1 is not initialized before using it.
Try this:

string* str1 = new string();
	str1->reserve(113);
	if(true)
	{
		string temp("I am alive now,but soon i will be dead");
		*str1= temp;	//i guess here the problem are. 
	}

	cout<<*str1;

	if (str1)
	{
		delete str1;
	}

[sysabod]

Thanks ,that is the point!

[1yR4jE8b]

I would just like to point out this line here:

if (str1)
	{
		delete str1;
	}

That, unless you explicity set a pointer to 0, it will never point to 0 by default. So the if statement is not only redundant, but useless, because if you WERE to set it to 0, trying to delete it would have no effect.