Question

Summary:
I’ve been playing with unix terminal a bit lately and decided to to build a tiny Objective-C app in order to test how passing arguments to “main” will actually execute. I’ve build the app keeping std=c99 in mind.

The test: everything works fine if I hard code values to argv and argc hence: argv[0] and argv[1] from the first few lines in main.

The problem: If I comment argv[0] and argv[1] out and run my app from the unix terminal the app will never work and that is why I’m wondering if terminal will append any funny characters that I am not aware of —

Here’s a snippet of the code:
1. Note that Dictionary is just a struct
2. Thoughts?

    int main(int argc, char * argv[])
{
    //argv[0] = "prog";
    //argv[1] = "four";

    NSLog(@"request from: %s, entered string: %s, # of arguments: %i", argv[0], argv[1], argc);

    //argc = 2;
    if (argc >= 2)
    {
        if (translate(argv, argc));
        else
            NSLog(@"%s", "Unable to find request in dictionary");
    }
    else
        NSLog(@"insufficient arguments");

    return 0;
}

    BOOL translate(char * search[], int size)
{
    const int buffer = 6;
    Dictionary dic[] =
    {{"one", "1"},
        {"two", "2"},
        {"three", "3"},
        {"four ", "4"},
        {"five", "5"},
        {"six", "6"}
    };

    char * temp = search[size - 1];
    NSLog(@"temp value: %s", temp);

    int i = 0;
    for (; i < buffer; ++i)
    {
        char * temp2 = dic[i].num;
        NSLog(@"steped into for loop - with currect struct value: %s", temp2);

        if (temp == temp2)
        {
            NSLog(@"steped into if stamtement");
            NSLog(@"%s", dic[i].translate);
            return YES;
        }
    }

    return NO;
}

Answer 1

So one last time…

You cannot compare strings using ==, because C ain’t JavaScript and == performs a numerical comparison on its operands. Instead of

if (temp == temp2)

you should write

if (strcmp(temp, temp2) == 0)

(and re-read a good C tutorial – in a decent one, “tricky” stuff like that is certainly included.)