Question

c++ Write the following 2 functions and test them. Both of them need to be recursive functions.

int sum(int n);

// recursive version to calculate the sum of 1 + 2 + ..... + n

int str_length(char s[];

// Returns length of the string s[] and the null character, '0\', is not counted in the length).

Example of program execution;

Enter a positive integer: 10 (user input)

The sum of 1+ 2+....+10 is: 55

Enter a sentence: Hello World! (user input)

The sentence contains 12 characters, including white spaces.

Do you want to run again? Y/N: y (user input)

repeat above steps...

Do you want to have another run? Y/N? n (user input)

Program ended with exit code: 0

What I have so far;

#include "stdafx.h"

#include <iostream>

using namespace std;

int str_length(char s[], int start);

int sum(int n);

char ch;

int main()

{

//characters

char sentence[100];

cout << "Enter a sentence: ";

cin.getline(sentence, 99);

cout << "There are " << str_length(sentence, 0) << " charcters in the sentence." << endl;

// sum

int n;

cout << "Enter a positive integer: ";

cin >> n;

cout << "Sum is " << sum(n) << endl;

}

int str_length(char s[], int start) {

if (s[start] == '\0')

return 0;

return 1 + str_length(s, start + 1); //recursive method to count char from 1 to '\0'

}

int sum(int n) {

if (n == 0)

return 0;

return n + sum(n - 1); //recursive method to calculate sum from 1 to n

}

I just need help with setting it up to ask the user if they want to run again and if they say yes, doing so. What I've tried so far either caused infinite loops or errors.

Answer 1

below i written complete C++ code as per the requirement.

Please note the below program has been tested on ubuntu 16.04 system and compiled using g++ compiler. This code will also work on code blocks and visual studio.

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Program:

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//#include "stdafx.h"

#include <iostream>

using namespace std;

int str_length(char s[], int start);

int sum(int n);

char ch;

int main()

{

//characters

char sentence[100];

char ans;

do

{

cout << "Enter a sentence: ";

cin.getline(sentence, 99);

cout << "There are " << str_length(sentence, 0) << " charcters in the sentence." << endl;

// sum

int n;

cout << "Enter a positive integer: ";

cin >> n;

cout << "Sum is " << sum(n) << endl;

cout<<"DO you want to continue(Y/y| N/n) ? ";

cin>>ans;

cin.ignore();

if(ans == 'N' || ans == 'n')

{

cout<<"Exiting the program..!!!"<<endl;

break;

}

}while(ans == 'Y' || ans == 'y');

cout<<endl;

return 0;

}

int str_length(char s[], int start)
{

if (s[start] == '\0')

return 0;

return 1 + str_length(s, start + 1); //recursive method to count char from 1 to '\0'

}

int sum(int n) {

if (n == 0)

return 0;

return n + sum(n - 1); //recursive method to calculate sum from 1 to n

}

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Sample Output:

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Kindly Check and Verify Thanks..!!!