What is the difference between new char (50) and new char [50]?

athena0554

Which one should be used to dynamically request a piece of memory when the program is running?
What is the difference between the two?

cat00019

new char (50) is equivalent to applying only one byte, and its value is ASCII = 50 character
new char [50] applies for space of 50 characters

athena0554

For char * p = new char [50];
I can * (p + 51) = 'a';
Or p [51] = 'a';
Even p [-10] = 'a';
1. Access the memory beyond the scope of the application and assign a value to it. Is this too dangerous?

2. After char * p = new char [50] in a program block, how to release it?
for (char * q = p; q <p + 50; p ++)
    delete q;

azqkmo

1. Address is dangerous
2.delete [] q;

makeyou

new char (50) is equivalent to applying only one byte, and its value is ASCII = 50 character
new char [50] applies for space of 50 characters
wrong! !!
The C ++ compiler gives two ways of writing to take into account the user's habits.
The former looks like function parameters.
The latter is for considerations like array applications.
There is no difference or problem between the two writing methods in actual operation.

adesaluis

makeyou

...
There is no difference or problem between the two writing methods in actual operation.
===========================================
You said it so categorically, you are wrong

athena0554

These two are still different
int * p = new char (97); // The string at p: "a" starts with a, followed by some spaces, it is estimated to end at\0
int n = strlen (p); // n = 16 the length of the string is variable

int * p = new char [97]; // pThe output string is: "Tun Tun Tun Tun Tun Tun Tun Tun Tun Tun Tun Tun Tun Tun Tun Tun Tun Tun Tun Tun Tun Tun Tun Tun Tun Tun Tun "Tuntun Tuntun Tuntun Tuntun Tuntun Tuntun Tuntun Tuntun"
int n = strlen (p); // n = 112 The value is uncertain, it is estimated that it will end when it encounters\0 in memory.

I'm confused about these two ways of writing! Which one should I use, and how much memory are allocated to them in these two ways?

leonim

Upstairs, right?
"new char (50) is equivalent to applying only one byte, and its value is a character with ASCII = 50" is right
#include <iostream.h>
int main ()
{
char * p = new char (50);
cout << * p << endl;
char * p1 = new char [50];
p1 = "pananwei";
cout << p1 << endl;
return 0;
}
The output is: 2
         pananwei

azqkmo

agree:
new char (50) is equivalent to applying only one byte internally, and its value is ASCII = 50. The character "is right
Disagree with whatmakeyousays

KTPOPO

Themakeyoubrothers did not understand that C ++ constructors are also valid for basic types ...