Detailed description of # define and typedef interchange in C Language

Copy codeThe Code is as follows: # include <stdio. h>
/* <--------- # Define string char * ----> */
Typedef char * string;

Int main (void)
{
String a [] = {"I", "like", "to", "fight ,"},
B [] = {"pinch,", "and", "bight ."};
Printf ("% s \ n", a [0], a [1], a [2], a [3], B [0], B [1], B [2]);
Return 0;
}

Replace the row of typedef with # define, and the given # define example cannot pass. However, you only need to add a character to the program.

=============================== Answers to this question ======================== ==============

There are two methods to define the pStr data type. What are the differences between the two? Which one is better?
Typedef char * pStr;
# Define pStr char *;

Answer and analysis:

Generally, typedef is better than # define, especially when there is a pointer. See the example below:
Typedef char * pStr1;
# Define pStr2 char *
PStr1 s1, s2;
PStr2 s3, s4;

In the preceding variable definition, s1, s2, and s3 are both defined as char *, while s4 is defined as char, which is not the expected pointer variable, the root cause is that # define is a simple string replacement, while typedef is a new name for a type.
In the preceding example, the define statement must be written as pStr2 s3, * s4; so that the statement can be executed normally.

So the program

Copy codeThe Code is as follows: # define string char *;
Int main (void)
{
String a [] = {"I", "like", "to", "fight ,"},
* B [] = {"pinch,", "and", "bight."};/* <-- this is where !! --*/
Printf ("% s \ n", a [0], a [1], a [2], a [3], B [0], B [1], B [2]);

Return 0;
}

======================================
Really clever!