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Difference between char* and const char*?
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char* is a mutable pointer to a mutable character/string.
const char* is a mutable pointer to an immutable character/string. You cannot change the contents of the location(s) this pointer points to. Also, compilers are requi...
Is char signed or unsigned by default?
In the book "Complete Reference of C" it is mentioned that char is by default unsigned.
7 Answers
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What is the difference between char s[] and char *s?
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The difference here is that
char *s = "Hello world";
will place "Hello world" in the read-only parts of the memory, and making s a pointer to that makes any writing operation on this memory illegal.
While doing:
char s[] = "Hello world";
puts the...
SQL/mysql - Select distinct/UNIQUE but return all columns?
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You're looking for a group by:
select *
from table
group by field1
Which can occasionally be written with a distinct on statement:
select distinct on field1 *
from table
On most platforms, however, neither of the above will work because the behavior o...
How do I trim leading/trailing whitespace in a standard way?
... allocated. The return
// value must NOT be deallocated using free() etc.
char *trimwhitespace(char *str)
{
char *end;
// Trim leading space
while(isspace((unsigned char)*str)) str++;
if(*str == 0) // All spaces?
return str;
// Trim trailing space
end = str + strlen(str) - 1;
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Can I embed a custom font in an iPhone application?
...Full name" of the font, which is visible by opening it up in Font Book and selecting: Preview --> Show Font Info
– electromaggot
Nov 20 '11 at 8:16
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How do I get textual contents from BLOB in Oracle SQL
...S of the text stored in the BLOB, CS of the database used for VARCHAR2) :
select utl_raw.cast_to_varchar2(dbms_lob.substr(BLOB_FIELD)) from TABLE_WITH_BLOB where ID = '<row id>';
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Printing hexadecimal characters in C
I'm trying to read in a line of characters, then print out the hexadecimal equivalent of the characters.
7 Answers
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const char * const versus const char *?
...ally be appropriate here, but perhaps the verbosity put off the developer.
char* the_string : I can change which char the_string points to, and I can modify the char to which it points.
const char* the_string : I can change which char the_string points to, but I cannot modify the char to which it po...
Delete column from SQLite table
... TRANSACTION;
CREATE TEMPORARY TABLE t1_backup(a,b);
INSERT INTO t1_backup SELECT a,b FROM t1;
DROP TABLE t1;
CREATE TABLE t1(a,b);
INSERT INTO t1 SELECT a,b FROM t1_backup;
DROP TABLE t1_backup;
COMMIT;
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