CODEWITHSUNDEEP
c++
Dreamer
Dreamer

Reputation: 25

How to point to the last letter in the string?

i'm trying to build a program that can find the order of a certain character in a string this is the code i made :

#include <iostream>
#include <string>
using namespace std;
int main()
{
    string word="banana";
    cout << "a = ";
    const char *pad = "";
    for (size_t i = 0; i < word.size(); i++)
    {
        if (word[i] == 'a')
        {
            cout << pad << (i + 1);
            pad = ", ";
        }
    } 
    cout << "\n";
    return 0; }

and it's working perfectly , the only matter is i want it to print out the last order only .. for more clarity : instead of printing out( a=2 , 4 , 6 ) in the last example i want it to print out (a=6)

Anyone can help?

Upvotes: 1

Views: 573

Answers (4)

Antoine
Antoine

Reputation: 14064

It's already implemented as the find_last_of and the rfind methods of std::string.

I recommend using one of these methods, but if you still want to implement yourself, you have to reverse the order to start from the end and not the begining, and I think you are looking for the break statement which stops the loop:

for (size_t i = word.size() - 1; i >= 0; --i)
{
  if (word[i] == 'a')
  {
    cout << pad << (i + 1);
    break;
  }
}

Break works like this:

break workflow

Upvotes: 4

Eric Fortin
Eric Fortin

Reputation: 7603

Reverse the loop

for (size_t i = word.size()-1; i >= 0; i--) {
   ...

If not for learning about loops, using the standard functions proposed in other answers are the right way to go.

Upvotes: 3

GMasucci
GMasucci

Reputation: 2892

The simplest way I can think of is to use the stl string find_Last_of function. Below is a small example:

#include <iostream>
#include <string>
using namespace std;
int main()
{
string word="banana";
int pos = word.find_last_of("a");
cout << "Last occurrence of the letter a is at position " << pos+1 << " array position " << pos <<endl ;
return 0; }

Upvotes: 2

Frerich Raabe
Frerich Raabe

Reputation: 94329

You can use std::string::rfind to get the index of the last occurrence of some character:

#include <string>
#include <iostream>

int main()
{
    std::string s = "banana";
    std::string::size_type pos = s.rfind( 'a' );
    if ( pos == std::string::npos ) {
        std::cout << "letter not found\n";
    } else {
        std::cout << "letter found at position " << pos + 1 << "\n";
    }
}

Upvotes: 2

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