Algorithm for Permuting in place

Problem: Given a set of numbers S = 1...n and a permutation PI(S), how can you rearrange elements in S in O(n) time with no extra space.

I don't like explaining things just code it., here's code below

#include
#include
#include
int a[10];
int b[10];

void ResetArray(){
    unsigned int i;
    for(i=0;i<10;i++){
        a[i] = i; 
    }
}
void swap_elements(unsigned int i,unsigned int j){
    int temp;
    temp = a[i];
    a[i] = a[j];
    a[j] = temp;
}
/*b is the swap list*/
void InplacePermute(int *perm){
    unsigned int i;
    for(i=0;i<10;i++){
        if(perm[i] < i){
            perm[i] = perm[perm[i]];
        }
        if(a[i] < i){
            perm[a[i]] = perm[i];
        }
        swap_elements(i,perm[i]);
    }
}

void PrintPermutation(void){
    unsigned int i;
    for(i=0;i<10;i++){
        printf("%d ",a[i]);
    }
}

int main(){
    int runs=10;
    unsigned int i;
    do{
        ResetArray();
        printf("Please enter the permutation of size 10, 10 unique digits from 0-9\n");
        for(i=0;i<10;i++){
         if(scanf("%d",&b[i])<=0){
            break;
         }
         assert(b[i] >=0 && b[i] <=10);
        }
        if(i<10){
            break;
        }
        InplacePermute(b);
        printf("The permutation is::");
        PrintPermutation();
    }while(1);
}

The following are testcases

7 3 2 1 4 8 9 0 5 6
8 9 1 2 5 6 7 3 4 0
1 2 3 4 5 6 7 8 0 9
1 3 4 8 9 0 7 6 5 2

Well this week has been a little productive, got the space for http://phaedrus.sourceforge.net a library of randomized algorithms
Have Fun.... Vamsi.