Modify a string

il dottore (2)
Hi,
i have a file like this (akagi.txt):

0.000 0.175 4 L
0.394 0.404 1 R
0.450 0.500 5 L short
0.707 0.747 1 L
0.772 0.822 5 R
0.867 0.917 5 R short

i read it with getline an put each line into "nota" string (see code)
how can i change for example all the 5 R in 4 R? 

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  #include <iostream>
#include <fstream>
#include <string>

using namespace std;

int main()
{
string nota;

    ifstream leggi("akagi.txt");

            if (leggi)
            {
                while (!leggi.eof())                            
                {
                    getline(leggi, nota);

                    if(nota......i don't know == 5 L)
                        ......
                        ......
                        
                    //cout << nota << endl;
                }
            }

    leggi.close();                                             

    return 0;
}


thank you
Aceix (1010)
il dottore (2)
Hi,
i'm very new in c++

I tryed to modify the "if......." (see the 1st post)
but got error:
terminate called after throwing an instance of 'out of range'
what <> : basic string::compare
Last edited on
whitenite1 (1104)
@il dottore

Here's one way to do it.

Instead of hard-coding the check, you could first ask the user what number and letter to check for, and then what to change them into. 
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#include <iostream>
#include <fstream>
#include <string>

using namespace std;

int main()
{
 string nota;

 ifstream leggi("akagi.txt");

 if (leggi)
 {
	while (!leggi.eof())                            
	{
	 getline(leggi, nota);
	 int len = nota.length();

	 for(int x=0;x< len; x++)
	 { 
		if (nota[x] == '5')
		{
		 if (nota[x+2] == 'R')// used +2 because of the space between the 5 and R
			nota[x] = '4';
		}
	 }                        
	 cout << nota << endl;
	}
 }
 leggi.close();                                             
 return 0;
}
Last edited on
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