Recursive Sort Function

I've written a program to recursively sort an array. However, I get the following error on line 11: syntax error before ']' token.

Here is the code:

//This program recursively sorts an array

#include<stdio.h>

void rec_sort(int values[], int n); 

main()
{
    int vals[4];
    vals[0] = 37; vals[1] = 48; vals[2] = 56; vals[3] = 63;
    printf("this array sorted: %x\n", rec_sort(vals[], 4));

    system("Pause"); 
    return 0;
}

void rec_sort(int values[], int n) {
//Base case
if (n<2) return;

int maxIndex=0;
int i;

//Find max item in array in indexes 0 through n-1
for(i=1; i<n;i++) {
      if(values[i] > values[开发者_StackOverflow社区maxIndex])
         maxIndex=i;

    }

    //Swap this element with one stored in n-1
    //Set temp to n-1, set n-1 in array to max, set max to temp
    int temp = values[n-1]; //Store temp as last element in array
    values[n-1] = values[maxIndex]; //Store last element as max value in array
    values[maxIndex] = temp; //temp will keep on changing, as array is sorted

    //Recursively sort the array values of length n-1
    sort(values, n-1); 
}

It looks like you're trying print out the whole array, which C won't do in one call to printf. Instead, you need a loop to iterate through the array and print out each number individually:

for (i=0; i<4; i++)
    printf("%x\n", vals[i]);

Since rec_sort isn't returning the array, you also need to invoke it separately from the call the printf, so you'd get something like:

// sort the data:
rec_sort(vals, 4);

// print the sorted values:
for (i=0; i<4; i++)
    printf("%x\n", vals[i]);

Just remove the [] on line 11. But this is a naive answer to your question, and won't get you far. There are other problems - the most obvious is the idea of printf(..., rec_sort(...)...);

Considering rec_sort has void return type, how do you expect printf() to understand what to do? I am not sure what you want either, but this should be at least a start for you.

printf("this array sorted: %x\n", rec_sort(vals[], 4));

but rec_sort() is void. Doesn't return anything

void rec_sort(int values[], int n)

Also, declare your main as int main()

The problem is in this:

rec_sort(vals[], 4)

What exactly do you want to do there? The [] is an index operation, so either you need to put a number in there, or you leave them out completely (if you want to talk about the whole array).

The first thing you should do is remove the square brackets:

printf("this array sorted: %x\n", rec_sort(vals, 4));

Second, note that rec_sort returns void, so you cant use the return value

you need

int i; // at the top of the main
// ...
rec_sort(vals, 4);
printf("this array sorted: ");
for(i = 0; i < 4; ++i) printf("%x ", vals[i]);
printf("\n");

Third: you need to call rec_sort again

Fourth: what are you tryin to do with the system statement?