Question

Many of my programs take in command-line arguments, one example is as follows:

a.out [file-name] [col#] [seed]

Then if I want to use the arguments, I have nice, easy-to-use functions such as:

atof(argv[..]) and atoi(argv[..])

I was wondering if such easy/simple functions exist for C++. I tried to simply do this:

cin >> col_num >> seed;

But that doesn’t work… It waits for an input (not command-line) and then outputs it…

Thanks

Answer 1

Solution 1:
You can use lexical_cast in place of atoi

int x = boost::lexical_cast<int>("12345"); 

Use boost::lexical_cast in try-catch block though. It throws boost::bad_lexical_cast when the cast is invalid.

Solution 2:
If you are not using Boost and need a standard C++ solution you can use streams.

std::string hello("123"); 
std::stringstream str(hello); 
int x;  
str >> x;  
if (!str) 
{      
  // The conversion failed.      
}