Cool c++ tricks

[adlep]

to get the output formated in hex:
int x = 14;

cout << hex << x;

 

[HigherGround]

or

cout << (void*)x;

 

[Armitage]

FYI on the predifined macros stuff ... here's a reference

I just had a need for the __cplusplus macro

 

[glugglug]

Originally posted by: arcain
And...

*(3 + p) is equivalent to *(p + 3)...

which means 3[a] is equivalent to a[3].

I doubt that very much, might have to try it.....

*(p+3) figures out that p is an int * and actually adds 3 * sizeof(int) = 12 before dereferencing.

3[a] shouldn't work for several reasons:
1. The compiler will complain that "3" is not a pointer type
2. Even if it treated 3 as a void*, adding the value of "a" as an int wouldn't work unless your array elements are 1 byte each.

 

[arcain]

Originally posted by: glugglug

Originally posted by: arcain
And...

*(3 + p) is equivalent to *(p + 3)...

which means 3[a] is equivalent to a[3].

I doubt that very much, might have to try it.....

*(p+3) figures out that p is an int * and actually adds 3 * sizeof(int) = 12 before dereferencing.

3[a] shouldn't work for several reasons:
1. The compiler will complain that "3" is not a pointer type
2. Even if it treated 3 as a void*, adding the value of "a" as an int wouldn't work unless your array elements are 1 byte each.

You should give it try..

Here, with non-bytesized elements:

#include <stdio.h>

int main()
{

float array[4] = { 0.0, 1.0, 2.0, 3.0 };
int i;

for (i = 0; i < 4; i++) {
printf("i = %d, array[ i ] = %e\n", i, array[ i ]);
printf("i = %d, i[array] = %e\n", i, i[array]);
}

printf("0[array] = %e\n", 0[array]);
printf("1[array] = %e\n", 1[array]);
printf("2[array] = %e\n", 2[array]);
printf("3[array] = %e\n", 3[array]);

return 0;
}

 

[prayansh]

here is a code i wrote to output all characters

char ch;
int i;
for (i=0;i<256;i++) //there are 255 characters in total
{ ch=i;
cout<<ch;
}

 

[EagleKeeper]

the more "tricks" you use; the more difficult it can be to read/understand code when trying to maintain it.

It may make you look cool but also be a PITA

and some of those tricks may be compiler or OS dependent.

 

[Merad]

the more "tricks" you use; the more difficult it can be to read/understand code when trying to maintain it.

It may make you look cool but also be a PITA

and some of those tricks may be compiler or OS dependent.

Nothing in the thread so far even really qualifies as a "trick".... it's all standard C++, some of it is just poor coding, like the infinite loop or "breaking" cin instead of using a debugger...

 

[brotj7]

C++ class templates are a cool little "trick". Can generalize a function to work for multiple datatypes.

 

[SunnyD]

Not really C++, and very Microsoft specific - in fact particularly ATL specific... but ATL has a handy set of macros. If you set at the top of a function:

USES_CONVERSION;

You can use a set of macros including W2A(), A2W(), etc. to convert string types between wide, ascii and mbcs without having to dick around with API function calls.