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How to Declare an Array of Strings in C

Ok, I know this is not a big deal, I just hate to deal with strings in C, so I’ll put the code here so I can copy-paste-modify whenever I need to do such things.

Purpose: declare an array of strings.

There are two cases here:

First case: You know the number of strings (say NUM_OF_STRINGS), and all strings have the same length – including the terminating ‘\0′ character – (say LENGTH_OF_STRING).

In this case, this is how the array can be declared:

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char* arrayOfStrings[NUM_OF_STRINGS];

for (i = 0; i < NUM_OF_STRINGS; i ++) {

        if (! (arrayOfStrings[i] = (char*)malloc(LENGTH_OF_STRING * sizeof(char))))

                  exit(-1);

};

Second case: Number of strings and length of each string is know only in runtime. In this case your code should look like this:

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char** arrayOfStrings;

int nStrings = GetNumberOfStrings();

int i;

if (! (arrayOfStrings = (char**) malloc(nStrings * sizeof(char*)))

        exit(-1);

for (i = 0; i < nStrings; i ++) {

        int strLen = GetStringLength(); /* Length includes terminating '\0' char */

        if (! (arrayOfStrings[i] = (char*) malloc(strLen * sizeof(char)))

               exit(-1);

};

That’s it. Don’t forget to free the allocated memory when you’re done.

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1. Array Indexing in C
2. Make Shell Scripts Executable By Default

Tags: Programming