Void fun1 (char * (p1)
{
P1=(char *) malloc (100);
}

Void fun2 ()
{
Char * p2=nullptr;
Fun1 (p2);
Strcpy (p2, "wind up xi clouds float in the sky");
The printf (p2);
}

Int main ()
{
Fun2 ();
return 0;
}

CodePudding user response:

Is sure to crash,
There are two other
The first:
Void fun1 (char * & amp; (p1)
The second
Void fun1 (char * * (p1)

CodePudding user response:

Collapse, change the pointer value parameter, but didn't change the pointer value of the argument, and assign nullptr collapses

CodePudding user response:

Please refer to the comments:
Void fun1 (char * (p1)
{
P1=(char *) malloc (100);//memory leak will happen here, in addition, the parameter variables p1 and local variables, so you don't output
}

Void fun2 ()
{
Char * p2=nullptr;
Fun1 (p2);//after perform this function, the p2 is still pointing nullptr
Strcpy (p2, "wind up xi clouds float in the sky");//do to nullptr address string copy, so the crash
The printf (p2);//crash has occurred, the p2 address is still pointing nullptr
}

Int main ()
{
Fun2 ();
return 0;
}
=================================================================================
The right to modify the following:
Void fun1 (char * * (p1)//in order to output address, need to use the secondary pointer
{
* p=(char *) malloc (100);//plus * is to save the address of the malloc to address
}

Void fun2 ()
{
Char * p2=nullptr;
Fun1 (& amp; P2);//holds the address of passed as a parameter
Strcpy (p2, "wind up xi clouds float in the sky");
The printf (p2);
Free (p2);//in order to prevent a memory leak, there needs to be free, please good coding habits oh.
}

Int main ()
{
Fun2 ();
return 0;
}

CodePudding user response:

You this kind of behavior, is similar to the reality, at the intersection of traffic through a red light, one is not killed, two is not killed, as through a red light is safe.
Everything has its rules, while occasionally don't obey the rules will not necessarily be punished, but can't think don't keep it's natural rule

CodePudding user response:

Looks like said: a virtual pointer is assigned the address space, so make a mistake; If only 2 statement pointer, and don't assign to nullptr, so they make mistakes?

CodePudding user response:

This shouldn't be a compiler error

CodePudding user response:

Value of C is essentially "pass"
Char * p1 is p1, pointing to the list of address
Char * * p1 is the address of the p1 itself

CodePudding user response:

?????????

CodePudding user response:

Please refer to "function parameter type of pointer in c + + pointer"
Wish I could help you!

CodePudding user response:

Value of C is essentially "pass"
Char * p1 is p1, pointing to the list of addresses// the value of "pass"
Char * * p1 is the address of the p1 itself//" value "

CodePudding user response:

Simple positive - Soft solution on the second floor

CodePudding user response:

I am a little white, squatting a great god

CodePudding user response:

Why do they don't have to type string string?

CodePudding user response:

Will appear as mentioned in the second floor and the fourth floor, but the most fundamental I would recommend
You understand value, preach Pointers and references to the difference between
This programming to yourself can make a big help, later met and problems can also be spread fast positioning

CodePudding user response:

Learning, seem to remember the memory in several areas, some return will have unpredictable

CodePudding user response:

Learning how to not snow back

CodePudding user response:

Generally in such must be func (char * * p) or func (char * & amp; p)

CodePudding user response:

Compile error, look again

CodePudding user response:

Learning to learn

CodePudding user response:

Learning, bosses is requested

CodePudding user response:

Value of C is essentially "pass"
Char * p1 is p1, pointing to the list of address
Char * * p1 is the address of the p1 itself

CodePudding user response:

Good good study!!!!!!!!!!!!!!!!!!!!!!!

CodePudding user response:

Firm involved in the relationship between the parameter value is a one-way transmission

CodePudding user response:

123

CodePudding user response:

Efforts to learn c + +!!!!!

CodePudding user response:

Learn to learn