strrev()

[Eva]

This is not supported under the UVA compiler right?

Then what's the fastest code to do this in C/C++?

And if I use standard string class how can I made this?

[sohel]

To reverse a string I use the following function

[cpp]
string_revers(char str[])
{
int i,l;
char t;
l = strlen(str) - 1;
for(i=0; i<l; i++)
{
t = str;
str = str[l];
str[l] = t;
l--;
}
}
[/cpp]

I don't think there is a faster algorithm than this simple function.
[/c]

[mbakht]

You don't need to go full length of the string. Going upto half the length of the string would be enough . Doing swap using XOR operation would make it even faster.....though that hardly matters.

[CDiMa]

You don't need to go full length of the string. Going upto half the length of the string would be enough . Doing swap using XOR operation would make it even faster.....though that hardly matters.

Actually it goes up to half the lenght...

Ciao!!!

Claudio

[mbakht]

I am extremely sorry. I didn't notice l--.

[anupam]

Actually, the beginers ace the problems very much. They normally choose the string problems and use strrev() and get CE.
I got many mail from the beginners about this topic.
--
Anupam

[Tahseen Mohammad]

for reversing any sequence you can use the STL algorithm function

std::reverse requries to #include<algorithm>

std::reverse(beginning_iterator, ending_iterator);

so for

Code: Select all

char a[10]; => std::reverse(a, a + 10);

and for

Code: Select all

string s; => std::reverse(s.begin(), s.end());

Or you can always use the handwritten function given by sohel.[/code]