Possible Duplicate:
length of array in function argument
My array size is 5. For example:
arrCustId[5]
How can I know how many Customer IDs are already present in my array? In short how to find length of array?
Do you mean how long is the array itself, or how many customerids are in it?
Because the answer to the first question is easy: 5 (or if you don't want to hard-code it, Ben Stott's answer).
But the answer to the other question cannot be automatically determined. Presumably you have allocated an array of length 5, but will initially have 0 customer IDs in there, and will put them in one at a time, and your question is, "how many customer IDs have I put into the array?"
C can't tell you this. You will need to keep a separate variable, int numCustIds (for example). Every time you put a customer ID into the array, increment that variable. Then you can tell how many you have put in.
If the array is statically allocated, use sizeof(array) / sizeof(array[0])
If it's dynamically allocated, though, unfortunately you're out of luck as this trick will always return sizeof(pointer_type)/sizeof(array[0]) (which will be 4 on a 32 bit system with char*s) You could either a) keep a #define (or const) constant, or b) keep a variable, however.
I'm not sure that i know exactly what you mean.
But to get the length of an initialized array,
doesn't strlen(string) work ??
Source: Stackoverflow.com