Question

I’m translating an example from C to Objective-C and have a questions.

C/C++ instruction:

buffer[i].str = population[i1].str.substr(0, spos) + population[i2].str.substr(spos, esize - spos);

How can I translate the part .substr(0, spos)

Buffer and population are vector using .
str is a string variable
i, i1, i2, spos and esize are integer variables.

Answer 1

Use the NSString methods.

You’ve got a lot of methods for creating substrings.
Mainly:

• substringFromIndex:
• substringWithRange:
• substringToIndex:

.substr(0, spos) may be translated to:

[ someString substringToIndex: spos ];

Note you will first need to convert your C++ string object to a NSString object.