adding strings

pantera · 08-20-2004, 04:17 AM

how to add two string
string1="its"
string2="done"
how can i get "its done" in a single string/char

gizmo_thunder · 08-20-2004, 04:35 AM

what are you programming in??

pantera · 08-20-2004, 05:27 AM

i am doing in C in linux

cppkid · 08-20-2004, 05:35 AM

If it is C/C++ you can do it by

#include <string.h>

strcat(string_one , string_two);

This funtion will concatinate string_one and string_two and store the resultant string in string_one.

If some other language you are using, then you can also use a loop to do that.
Make a string of size equal to size of string_one + string_two +1 and then copy both in that string with a loop char by char, Like

for (i=0; i<string_one.length();i++)
reult_string[i] = string_one[i];

for (i=string_one.length(); i<string_one.length()+string_two.length();i++)
reult_string[i] = string_two[i - string_one.length()];

reult_string[i+1] = '\0';

For the second case its just the logic for that, you can use the loops or arrays in the syntax of your own language.

cppkid · 08-20-2004, 05:41 AM

Ok if you are doing in c++.

To copy a string you can use.
strcpy(destination , source);

To add two strings you can use.
strcat(destination , source);

In strcat you destination string must be of enough size to hold both the strings.

If string1 is 10 chars and string 2 is of 5 chars then you can declair a string 3 with 10+5+1=16 char.
One extra char for '\0' string terminater.

Then copy first string in string3 and then concatinate it with string2.

strcpy(string3 , string1);
strcat(string3 , string2);

kev82 · 08-20-2004, 08:04 AM

by cppkid
Ok if you are doing in c++.

this is not particularly relevant to pantera but in case anyone else reads this thread i would like to point out that you would be better using c++ strings rather than c strings in c++ because they have nice operators defined for them, the code in c++ would become

Code:

#include <string>

using std::string;

void somefunc() {
    string s1="its";
    string s2="done";

    s1+=(" "+s2);
}

if you do want to use c standard library header files in c++ then they should be prefixed with c and lose the .h, so #include <string.h> becomes #include <cstring>

finally for the c-string functions you should really use the n-versions as this will greatly help to reduce the chance of nasty things like buffer overflow.