we have a direct support for the logarithmic functions in c.
include math.h in your program and this solves the problem of find ln 3..
this ln 3 is similar to log(3);
i think the site mentioned by mahsa_c++ also helps your problem..
please help me in using system(); in c++
System() functions in C or C++ provides you to perform command prompt ( or Shell) command in your program. usually typing the very same command that u do in a shell, in the argument field of the system( ... ) function will lead to the performance of that command.
For example in a cmd ( command prompt ) in windows typing "cls" clears the console. now typing