Question

c class

ex in the 2pic

Question 1: A. Write a recursive function Ecursive function that converts a string of digits into an integer. The function returns an integer that is converted from the original string 's'. int convertToint char *s); B. What's BIG-O notation of your function in part A.

Answer 1

A)

CODE

#include<stdio.h>

#include <math.h>

int arrLength(char input[]){

  int len = 0;

  for(int i =0;input[i] != '\0';i++){

    len++;

  }

  return len;

}

int stringToInteger(char arr[], int lastIndex){

  //Base Case

  if(lastIndex == 0){

    return arr[lastIndex] - '0';

  }

  //Recursive Call

  int res = stringToInteger(arr, lastIndex-1);

  int a = arr[lastIndex] - '0';

  return res * 10 + a;

}

int main() {

char arr[] = {'1', '2', '3', '4'};

int length = arrLength(arr);

printf("%d", stringToInteger(arr, length-1));

}

B)

The time complexity of this method is O(N) where N is the number of digits in the number.