C++ Smallest index in int array

Find the smallest index in an int array.

#include <stdio.h>


// *** find the smallest index in an int array ***
int smallestIndex(int arr[], int len, int searchFrom){
      if (len < searchFrom - 1)
         return -1;  // search out of range.
      int ans = searchFrom;
      for (int i = searchFrom; i < len ; i=i+1)
         if (arr[ans] > arr[i])
            ans = i;
      return ans;
}

// *** swap two values in int array ***           
void swap (int arr[], int len , int ind1, int ind2) {
      if (ind1 < 0 || ind2 < 0 || ind1 > len-1 || ind2 > len-1)
         return ;  // index out of range.
      int tmp = arr[ind1];
      arr[ind1] = arr[ind2];
      arr[ind2] = tmp;      
}      
  // *** sort an int array ***



void sort(int arr[], int len) {
      for (int i=0; i< len; i = i+1) {
         int minInd = smallestIndex(arr, len, i);
         swap(arr, len, i, minInd);
      } 
}
      


// *** prints an int array ***
void printArray (char Sentance[], int arr[], int len) {
   printf("%s ", Sentance);
   for(int i=0; i < len; i = i+1)
      printf("%d, ", arr[i]);   
   printf("\n");
}

void main (){
	int arr[] = {16,3,56,3,1,444,-12,29,13};
	int arrLen = sizeof(arr)/sizeof(int);
	printArray ("The original elements are: ", arr, arrLen);
    sort(arr, arrLen);
	printArray("The sorted elements are: ", arr, arrLen);
}