tabiki ben değidle bir arkadasım hemen alıyorum kodları ordan buraya ileticem

Ek Olarak: import java.util.Scanner;

public class HomeWork {
public static void main (String args []){
Scanner input = new Scanner (System.in);
System.out.println("Choose one!");
System.out.println("1: Contains \t 2: giveDigits");
System.out.println("3: replaceAll \t 4: compareTo \t 5: Quit");
int n= input.nextInt();
String temp1 = "";
String temp2 = "";
String temp3 = "";
String s1, s2, s3;
switch (n) {

case 1:
s1 = Scan(temp1);
s2 = Scan (temp2);
int q = contains(s1,s2);
System.out.println(q);

break;

case 2:
s1 = Scan(temp1);
String x = giveDigits(s1);
System.out.println(x);

break;

case 3:
s1 = Scan(temp1);
s2 = Scan (temp2);
s3 = Scan (temp3);

String y= replaceAll(s1,s2,s3);
System.out.println(y);
break;

case 4:
String s6 = Scan(temp1);
String s7 = Scan (temp2);

int Value = compareTo(s6,s7);
System.out.println(Value);

break;

case 5:
System.out.println("Bye..");

break;

default:
if (n<=0 || n > 5) {
System.out.println("ERROR!!! You entered wrong number!");
}

}
input.close();
}

public static String Scan (String a) {
Scanner input = new Scanner (System.in);
System.out.print("Enter a string: ");
String result = input.nextLine();

return result;
}


public static String giveDigits (String s1){
String x="";

for ( int i=0; i<= s1.length()-1; i++){
int result= s1.charAt(i);
if(result>=48 && result<=57){
char a = s1.charAt(i);
x+= a;
}
}
return x;
}

public static int compareTo (String s6, String s7) {
int result=0;
if(s6.length() == s7.length()){
for(int i =0; i<= s6.length()-1; i++){
if(s6.charAt(i) > s7.charAt(i)) {
result = 1;

}
else if(s6.charAt(i) < s7.charAt(i)) {
result = -1;
}


}
}
else {
int stringLength = Math.min(s6.length(), s7.length());
for(int i =0; i<= stringLength-1; i++){
if(s6.charAt(i) > s7.charAt(i)) {
result = 1;

}
else if(s6.charAt(i) < s7.charAt(i)) {
result = -1;
}
else if(s6.charAt(i) == s7.charAt(i)) {
if(s6.length()>s7.length()){
result=1;
}
else{
result=-1;
}
}


}
}
return result;
}

public static String replaceAll(String s1,String s2, String s3) {
String result="";
for (int i=0; i<=s1.length()-1; i++){
if(s1.charAt(i)!=s2.charAt(0)){
result+=s1.charAt(i);

}
else {
String a="";
int b=i;

for(int j=0; j<=s2.length()-1;j++){
while (s1.charAt(b)==s2.charAt(j)){
//a +=s2.charAt(j);
b++;

} int z = Math.abs(s2.length()-s3.length());
i=b-z;
}
result+=s3;
}
}return result;
}

public static int contains(String s1, String s2){
int b=0;
for(int i=0; i<=s1.length()-1; i++){
int j=0;
while(s1.charAt(i)==s2.charAt(j)){
for(j=0; j<=s2.length()-1; j++) {
if(s1.charAt(i)==s2.charAt(j)){
b = i;
}
}
break;

}
} return b;

}
}