day26-5String repalce(char oldChar, char newChar): 将字符串中的老字符,替换为新字符

public static void main(String[] args){
fu4();
}

public static void fu4(){
String a="asd211";
System.out.print("原函数"+a+" ");
String a1=a.replace("1","0");
System.out.println("修改后"+a1);
}