Working with Strings in Memory

Working with Strings in Memory

C strings are arrays, so they also inherit array rules. Let's see the practical ones.

Strings need room

A string variable is a fixed-size array. Copying a longer string into a small buffer overflows it:

char small[5];
strcpy(small, "much too long!!");   // danger: overflow

Make the buffer big enough

char name[50];
strcpy(name, "Ada Lovelace");

String as memory

Strings share everything arrays share: start at index 0, contiguous bytes, and they "decay" to a pointer when passed around.

One more: string literal is read-only

char *p = "fixed text";
p[0] = 'X';   // often bad: modifying a string literal

Use a char array (not a pointer) if you'll modify the text.

TL;DR

• Strings are fixed-size arrays; match the buffer to the data.
• Copying too much memory is called overflow.
• Prefer a char array when you will modify the text.
• Know the length before you copy.