Q:

Java: I can add as period to another period?

This program tells me which time a start date and an end, now I ask you whether you want to enter another period when you s  (yes) adds the starting period, but this want to join with above, for example, I add the following:
16/08/1993 - 09/09/2014 = 21 years, 0 months, 24 days.
14/02/1995 - 18/05/2001 = 6 years, 3 months, 35 days
Total:.................................27 years, 3 months y 59 days
NOTE: I do not know if something is wrong and try everything. I am new to java.
public void diferencia(){
char seguir=0;
Scanner teclado =new Scanner(System.in);
do{
System.out.println("day/Month/year ");
System.out.println("Write the first date: ");
String dayini = teclado.next();
System.out.println("write the second date: ");
String dateactual = teclado.next();

String[] aFechaIng = dateini.split("/");
Integer dayini = Integer.parseInt(aFechaIng[0]);
Integer monthini = Integer.parseInt(aFechaIng[1]);
Integer yearini = Integer.parseInt(aFechaIng[2]);

String[] aFecha = dateactual.split("/");
Integer dayactual= Integer.parseInt(aFecha[0]);
Integer monthactual = Integer.parseInt(aFecha[1]);
Integer yearactual = Integer.parseInt(aFecha[2]);

int b = 0;
int days = 0; //DAYS
int month = 0;  //MONTH
int years = 0;  //YEARS
int months = 0;  //MONTHS
month = monthini - 1;
// LEAP YEAR
if(month==2){
if ((yearactual % 4 == 0) && ((yearactual % 100 != 0) || (yearactual % 400 == 0))){
b = 29;
}else{
b = 28;
}
}else if(month <= 7){
if(month == 0){
b = 31;
}else if(month % 2==0){
b = 30;
}else{
b = 31;
}
}else if(month > 7){
if(month % 2 == 0){
b = 31;
}else{
b = 30;
}
}
if((yearini > yearactual) || (yearini == yearactual && monthini > monthactual) ||
(yearini == yearactual && monthini == monthactual && dayini > dayactual)){
// errors
System.out.println("The start date must be minor ");
}else{ //time periods
if(monthini <= monthactual){
years = yearactual - yearini;
if (dayini <= dayactual){
mmonths = monthactual - monthini;
days = b - (dayini - dayactual);
}else{
if(monthactual == monthini){
years = years - 1;
}
months = (monthactual - monthini - 1 + 12) % 12;
days = b - (dayini - dayactual);
}
}else{
years = yearactual - yearini - 1;
//System.out.println("Años?¿: " + anios);
if(dayini > dayactual){
months = monthactual - monthsini - 1 + 12;
days = b - (dayini - dayactual);
}else{
months = monthactual - monthini + 12;
days = dayactual - dayini;
}
}
}

System.out.println("Years: "+years);
System.out.println("Months: "+months);
System.out.println("Days: "+days);
System.out.println("You want to add another period?? ");
seguir = teclado.next().charAt(0);
}while(seguir!='n');
}//finish method diferencia

A:

Before begining your loop create three variables wich are totalAnios (totalYears), totalMeses (totalMonths) , totalDias (totalDays) and initialize them to 0.
   int totalAnios = 0;
   int totalMeses = 0;
   int totalDias = 0; 
   do {
     ....
   }

And before closing the loop (before while(...) )  you have to add the difference of years, months and days to the previous varibales you created ( totalAnios , totalMeses  , totalDias ) and print the result.
do {
 ... 
 /* your calculation goes here */

   totalAnios += anios;
   totalMeses += meses;
   totalDias  += dias;

            System.out.println("total : " + totalAnios + " " + totalMeses + " " + totalDias);
} while (seguir != 'n');

Each time the user choose to stay in the loop, we sum the previous results and print the total.
By the way, next time don't forget to format your code and put variables in english ;) .

