Question

Why this code always return 0

public int loveCal(String bname, String gname) {

    char[] boy_name = bname.toLowerCase().toCharArray();
    char[] girl_name = gname.toLowerCase().toCharArray();

    int boy = 0;
    int girl = 0;
    int love = 0;

    for(int i = 0; i < bname.length(); i++)
        boy += (int) boy_name[i];
    for(int i = 0; i < gname.length(); i++)
        girl += (int) girl_name[i];

    if( boy > girl )
        love = (girl/boy)*100;
    else
        love = (boy/girl)*100;

    return love;
}

Answer 1

You’re always performing integer arithmetic – and always dividing one non-negative integer by a greater one. That will always give zero. Multiplying that zero by 100 doesn’t help.

The simplest way of fixing this is to just multiply by 100 first:

return boy > girl ? (girl * 100) / boy : (boy * 100) / girl;

That sticks with integer arithmetic, but avoids the truncation to zero by making it something like (600 / 9) instead of (6 / 9) * 100.