Hello,
I just have a simple question on the use of the qsort function. Say I have an array of strings such as:
How would I sort this with qsort? I'm just a little confused on what to pass to qsort as parameters. Also, how would it be done with an array whose elements aren't set at the beginning (i.e., the array is being filled up from input from stdin)? Thanks.Code:char* str[] = {"Hello","Am","Where","Stuff"}
qsort()
gg
You'd probably get an answer from searching this board for 'qsort'
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qsort() is used to sort 'blocks' of data. Usually, qsort() has a callback routine (your own code) that actually does the compare and returns whether one data 'block' is < or = or > the other data 'block'.
As for what to pass, you pass the address of the data block. This can be an address to any nonmoving element in RAM. qsort() sorts pointers based on your evaluation of their contents.
A 'block' of data could even be a structure:
The callback might compare 'myVal' fields.Code:typedef struct { int myVal; long otherData[16]; long moreData[32]; }dataBlock;
Usually the comparison is really just a subtraction:
Code:... /* from inside the callback */ return(mystruc1->myVal - myStruc2->myVal); }
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