CODEWITHSUNDEEP
c++stringchar
CodeFu
CodeFu

Reputation: 165

difference between char str[m][n] and char *str[] when passing to function

 1. char *names[5]={"Web","Security","Software","Hello","Language"};

 2. char names[5][30]={"Web","Security","Software","Hello","Language"};

what is the difference between these two ?

One I know is that (1.) first one can have desired length of string while (2.) second one can have string 29 characters with '\0'

But I am confused that what's the difference when they are passed to function and how they are passed ?

Please elaborate I am new to C++ ....

Upvotes: 0

Views: 371

Answers (1)

molbdnilo
molbdnilo

Reputation: 66371

The first one shouldn't compile unless you add a const; const char *names[5] = ....

Once you fix that, the first is an array of pointers, the second is an array of arrays.

If you pass them to a function, the first will decay into a pointer to a pointer, const char**, while the second will decay into a pointer to an array with 30 elements, char(*)[30].

That is,

void pointers(const char**);
void arrays(char(*)[30]);

const char *names[5]={"Web","Security","Software","Hello","Language"};
pointers(names); // Good
arrays(names); // Bad

char names[5][30]={"Web","Security","Software","Hello","Language"};
pointers(names); // Bad
arrays(names); // Good

Upvotes: 3

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