string - Java compareTo method. The student.compareTo method should return -

i ask write student.compareto method should return 0 if first name of 2 students , last name of 2 students same. should return negative value if student's name sort lexicographically lower 1 passed in. should return positive value if student's name sort lexicographically higher 1 passed in.

here code far. negative value , positive value should fixed value or should use compareto value?

public int compareto(student){ int comparison = (this.firstname.compareto(student.firstname)); int comparison2 = (this.lastname.compareto(student.lastname));  if (comparison == comparison2)     return 0; else if ((comparison=0 && comparison2<0) ||(comparison<0 && comparison2=0)     return -1; else     return 1; } 

this code. wondering if did correctly

public int compareto(student){     string studentinfo=(this.firstname + this.lastname); string studentinfo2=(s1.firstname + s1.lastname); int comparison =studentinfo.compareto(studentinfo2); return comparison; } 

this complicated...

chain comparisons; if first 1 returns 0, run second; if second returns 0, run third; etc.

that is, return first comparison result non zero, or last one. example:

@override public int compareto(final student other) {     int ret = firstname.compareto(other.firstname);     if (ret != 0) // no need go further         return ret;      // hypothetic second comparison before lastname     // ret = foo.compareto(other.foo);     // if (ret != 0)     //     return ret;      // rinse, repeat...      // previous comparisons returned 0,      // return result of last comparison     return lastname.compareto(other.lastname); } 

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guava has nice utility class that:

@override public int compareto(final student other) {     return comparisonchain.start()         .compare(firstname, other.firstname)         .compare(lastname, other.lastname)         .result(); }