edit the tag "ID3" of an mp3 [closed]

I need to rewrite the TAG of an mp3 file, "change the name, album, date, etc." This is the code I use to read the information of an mp3:

//ID3 scan

#include <iostream>
#include <cstring>

using namespace std;

typedef unsigned char    byte;
typedef unsigned int     unit;

typedef struct {byte b3,b2,b1,b0;}sint;

struct header {
     char  mark [3];
     byte  version [2];
     byte flags ;
     sint  size ;  
};

struct frame {
    char id [4];
    sint size ;
    byte flags [2];
};

uint unsych (sint value ){
     return value.b0|value.b1<<8|value.b2<<16|value.b3<<24;
 }

int main(){
    FILE*file=fopen ("/home/caeforga/Descargas/cancion.mp3","r");
    if (!file){
        cout<<"file not found"<<endl;
        return 0;
    }
    header hd;
    fread(&hd,10,1,file);
    if(strncmp(hd.mark,"ID3",3)!=0){
        cout<< "this file has'nt TAG"<<endl;
        fclose(file);
        return 0;
    }
    cout<< "version:    "
        <<(int)hd.version[0]<<"."<<(int)hd.version[1]<<endl;
    cout << "flags:   "<<(int)hd.flags<<endl;
    cout<< " size:    "<<unsych(hd.size)<<endl;
    if (hd.version[0]<3){
        cout <<"version no complatible "<<endl;
        fclose (file);
        return 0;
    }
    while (true) {
        frame fr;
        fread (&fr,10,1,file);
        if (fr.id[0]<'A')  break;
        cout<< endl;
        cout<< fr.id[0]<<fr.id[1]<<fr.id[2]<<fr.id[3]<< "  " << unsych(fr.size)<<" bytes "<< endl ;
        if (fr.id[0]!='T'){
            fseek(file, unsych( fr.size), SEEK_CUR);
        }
        else {
            char buffer;
            for (uint i =0;i <unsych(fr.size); i++){
                fread(&buffer ,1,1,file);
                if(buffer >=32&& buffer <=126){
                    cout<< buffer;
                }
            }
            cout <<endl;
        }
    }
    fclose (file );
    return 0;
}