task1

#include using namespace std; #define null 0 bool dup(int numbers[],int length,int *duplication) { if(numbers==null||length<=0) { return false; }

for(int i=0;i<length;i++) { if(numbers[i]<0||numbers[i]>length-1) return false; }

for(i=0;i<length;i++) { while(numbers[i]!=i) { if(numbers[i]==numbers[numbers[i]]) { *duplication=numbers[i];

			return true;
	}

  
	int temp=numbers[i];
	numbers[i]=numbers[temp];
    numbers[temp]=temp;
}

}

return false;

} int main() { int numbers[]={0,1,2,2,5,4,3}; int length=0; int duplication; length = sizeof(numbers)/sizeof(int); dup(numbers,length,&duplication); cout<<duplication<<endl; return 0; }