Program for Derivative of a Polynomial

18 Nov, 2021
Given a polynomial as a string and a value. Evaluate polynomial’s derivative for the given value. Note: The input format is such that there is a white space between a term and the ‘+’ symbol
The derivative of p(x) = ax^n is p'(x) = a*n*x^(n-1)Also, if p(x) = p1(x) + p2(x) Here p1 and p2 are polynomials too p'(x) = p1′(x) + p2′(x) 
Input : 3x^3 + 4x^2 + 6x^1 + 89x^0
        2             
Output :58 
Explanation : Derivative of given
polynomial is : 9x^2 + 8x^1 + 6
Now put x = 2
9*4 + 8*2 + 6 = 36 + 16 + 6 = 58  
            
Input : 1x^3
        3
Output : 27
We split the input string into tokens and for each term calculate the derivative separately for each term and add them to get the result. 
C++
Java
Python3
C#
Javascript
// C++ program to find value of derivative of// a polynomial.#include <bits/stdc++.h>using namespace std; long long derivativeTerm(string pTerm, long long val){    // Get coefficient    string coeffStr = "";    int i;    for (i = 0; pTerm[i] != 'x'; i++)        coeffStr.push_back(pTerm[i]);    long long coeff = atol(coeffStr.c_str());     // Get Power (Skip 2 characters for x and ^)    string powStr = "";    for (i = i + 2; i != pTerm.size(); i++)        powStr.push_back(pTerm[i]);    long long power = atol(powStr.c_str());     // For ax^n, we return anx^(n-1)    return coeff * power * pow(val, power - 1);} long long derivativeVal(string& poly, int val){    long long ans = 0;     // We use istringstream to get input in tokens    istringstream is(poly);     string pTerm;    while (is >> pTerm) {         // If the token is equal to '+' then        // continue with the string        if (pTerm == "+")            continue;                // Otherwise find the derivative of that        // particular term        else            ans = (ans + derivativeTerm(pTerm, val));    }    return ans;} // Driver codeint main(){    string str = "4x^3 + 3x^1 + 2x^2";    int val = 2;    cout << derivativeVal(str, val);    return 0;}
// Java program to find value of derivative of// a polynomialimport java.io.*;class GFG{   static long derivativeTerm(String pTerm, long val)  {     // Get coefficient    String coeffStr = "";    int i;    for (i = 0; pTerm.charAt(i) != 'x' ; i++)    {      if(pTerm.charAt(i)==' ')        continue;      coeffStr += (pTerm.charAt(i));    }     long coeff = Long.parseLong(coeffStr);     // Get Power (Skip 2 characters for x and ^)    String powStr = "";     for (i = i + 2; i != pTerm.length() && pTerm.charAt(i) != ' '; i++)    {      powStr += pTerm.charAt(i);    }     long power=Long.parseLong(powStr);     // For ax^n, we return a(n)x^(n-1)    return coeff * power * (long)Math.pow(val, power - 1);  }  static long derivativeVal(String poly, int val)  {    long ans = 0;     int i = 0;    String[] stSplit = poly.split("\\+");    while(i<stSplit.length)    {      ans = (ans +derivativeTerm(stSplit[i], val));      i++;    }    return ans;  }   // Driver code  public static void main (String[] args) {     String str = "4x^3 + 3x^1 + 2x^2";    int val = 2;     System.out.println(derivativeVal(str, val));  }} // This code is contributed by avanitrachhadiya2155
# Python3 program to find# value of derivative of# a polynomial.def derivativeTerm(pTerm, val):     # Get coefficient    coeffStr = ""     i = 0    while (i < len(pTerm) and           pTerm[i] != 'x'):        coeffStr += (pTerm[i])        i += 1             coeff = int(coeffStr)     # Get Power (Skip 2 characters    # for x and ^)    powStr = ""    j = i + 2    while j < len(pTerm):        powStr += (pTerm[j])        j += 1        power = int(powStr)     # For ax^n, we return    # a(n)x^(n-1)    return (coeff * power *            pow(val, power - 1)) def derivativeVal(poly, val):     ans = 0    i = 0    stSplit = poly.split("+")        while (i < len(stSplit)):             ans = (ans +               derivativeTerm(stSplit[i],                              val))        i += 1     return ans # Driver codeif __name__ == "__main__":     st = "4x^3 + 3x^1 + 2x^2"    val = 2       print(derivativeVal(st, val)) # This code is contributed by Chitranayal
// C# program to find value of derivative of// a polynomialusing System; class GFG{ static long derivativeTerm(string pTerm, long val){     // Get coefficient    string coeffStr = "";    int i;         for(i = 0; pTerm[i] != 'x'; i++)    {        if (pTerm[i] == ' ')            continue;                     coeffStr += (pTerm[i]);    }         long coeff = long.Parse(coeffStr);         // Get Power (Skip 2 characters for x and ^)    string powStr = "";     for(i = i + 2;        i != pTerm.Length && pTerm[i] != ' ';        i++)    {        powStr += pTerm[i];    }         long power = long.Parse(powStr);         // For ax^n, we return a(n)x^(n-1)    return coeff * power * (long)Math.Pow(val, power - 1);} static long derivativeVal(string poly, int val){    long ans = 0;         int i = 0;    String[] stSplit = poly.Split("+");         while (i < stSplit.Length)    {        ans = (ans +derivativeTerm(stSplit[i], val));        i++;    }    return ans;} // Driver codestatic public void Main(){    String str = "4x^3 + 3x^1 + 2x^2";    int val = 2;         Console.WriteLine(derivativeVal(str, val));}} // This code is contributed by rag2127
<script>// Javascript program to find value of derivative of// a polynomial function derivativeTerm( pTerm,val){    // Get coefficient    let coeffStr = "";    let i;    for (i = 0; pTerm[i] != 'x' ; i++)    {      if(pTerm[i]==' ')        continue;      coeffStr += (pTerm[i]);    }      let coeff = parseInt(coeffStr);      // Get Power (Skip 2 characters for x and ^)    let powStr = "";    for (i = i + 2; i != pTerm.length && pTerm[i] != ' '; i++)    {      powStr += pTerm[i];    }      let power=parseInt(powStr);      // For ax^n, we return a(n)x^(n-1)    return coeff * power * Math.pow(val, power - 1);} function derivativeVal(poly,val){    let ans = 0;      let i = 0;    let stSplit = poly.split("+");    while(i<stSplit.length)    {      ans = (ans +derivativeTerm(stSplit[i], val));      i++;    }    return ans;}  // Driver codelet str = "4x^3 + 3x^1 + 2x^2";let val = 2;document.write(derivativeVal(str, val));  // This code is contributed by ab2127</script>
Output: 
59
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