Question

c++

int count(const string& str, char a);

Write a recursive function that finds the number of occurrences of a specified letter in a string. For example,count("Welcome",’e’)returns 2.

Answer 1

#include <iostream>
using namespace std;

int count(const string& str, char a){
    if(str.length()>0){
        if(str[0]==a){
            return 1+count(str.substr(1,str.length()),a);
        }
        else{
            return count(str.substr(1,str.length()),a);
        }
    }
    else{
        return 0;
    }
}

int main()
{
    cout<<count("Welcome",'e')<<endl;
    return 0;
}

2

int count(const string& str, char a){
    if(str.length()>0){
        if(str[0]==a){
            return 1+count(str.substr(1,str.length()),a);
        }
        else{
            return count(str.substr(1,str.length()),a);
        }
    }
    else{
        return 0;
    }
}