CODEWITHSUNDEEP
c++
Slazer
Slazer

Reputation: 4990

const char * testing equality with a character

I would like to return "jackpot" if there is only one character in "toParse" and the character is either "+" or "0". What is the most elegant way to do this? I tried this but apparently it does not work as it returns "jackpot" all the time for unknown reason.

char* ParseNRZI::parse(const char* toParse){
    if (toParse=="+"||toParse=="0")
        return "jackpot";
}

Upvotes: 1

Views: 1612

Answers (2)

billz
billz

Reputation: 45420

use strcmp if you compare C style pointers to char

char* ParseNRZI::parse(const char* toParse)
{
    if (strcmp(toParse, "+") == 0 ||
        strcmp(toParse, "0") == 0)
    {
        return "jackpot";
    }
    return "something else";
}

Or if you use std::string you can use operator== freely

std::string ParseNRZI::parse(const std::string& toParse)
{
    if (toParse == "+" || 
        toParse == "0") 
    {
        return std::string("jackpot");
    }
    return std::string("something else");
}

For design point of view, you are wring a check function not a real parsing function. Then you can rewrite your function to:

bool isJackpot(const std::string& value) 
{
    if (toParse == "+" || 
        toParse == "0") 
    {
        return true;
    }
    return false;
}

and it can simplified to:

bool isJackpot(const std::string& value) 
{
  return value.find_first_of("0+") != std::string::npos;
}

Note: your function doesn't always return char* in all branches it will invoke undefined behavior when toParse is not + or 0. Make sure all your function branches return a value when function return type is not void.

Upvotes: 4

edwinc
edwinc

Reputation: 1676

    const char* ParseNRZI::parse(const char* toParse) const
    {
      if (( toParse != 0 ) &&
          ( toParse[0] == '+' || toParse[0] == '0' ) &&
          ( toParse[1] == 0 )
         )
        return "jackpot";

      return "";

    }

Upvotes: 0

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