En forelesningsbit med en mentor som en del av Codegym University-kurset. Meld deg på hele kurset.


"Hei, Amigo. I dag skal vi snakke om if/else-uttalelser ."

"Programmer ville være til liten nytte hvis de ikke reagerer på endrede ytre omstendigheter. Et program må vite hvordan det skal tilpasse seg omstendighetene og utføre én handling i ett tilfelle og andre handlinger i andre tilfeller. I Java oppnås dette ved å bruke 'if/else statement' - en spesiell konstruksjon som gjør det mulig å utføre forskjellige kodeblokker hvis en betingelse er oppfylt."

"Den består av tre deler: ' betingelse ', ' kommando 1 ' og ' kommando 2 '. Hvis betingelsen er sann, utføres ' kommando 1 ', ellers utføres 'kommando 2' . Disse kommandoene blir aldri begge utført. Utsagnet ser mer eller mindre slik ut:"

Kode for en if/else-setning
if (condition)
    command_1;
else
    command_2;

"Så spennende! Jeg tror den uttalelsen vil gjøre programmering mye mer interessant!"

"Jepp. Her er et par eksempler for deg:"

Kode Forklaring
1
if (a < b)
    System.out.println("A is less than B");
else
    System.out.println("B is less than  A");
Hvis a er mindre enn b, vil den første kommandoen bli utført. Ellers vil den andre kommandoen bli utført . Kommandoene blir aldri begge utført.
2
if (a < b)
{
    System.out.println("A is less than B");
    System.out.println("B is greater than A");
}
else
{
     System.out.println("B is less than A");
     System.out.println("A is greater than B");
}
Du kan erstatte en kommando med en kodeblokk. Resten er det samme.
3
if (a < b)
{
    a = 0;
}
else
{
}
Du kan utelate den andre blokken hvis den er tom.
Disse tre eksemplene er helt like.
Du kan utelate de krøllede parentesene hvis du bare trenger å utføre én kommando. Hvis du har mer enn én kommando, må du beholde parentesene.
4
if (a < b)
{
    a = 0;
}
5
if (a < b)
    a = 0;

"Diego ba meg bare gi deg noen få oppgaver."

2
Oppgave
Java Syntax,  nivålekse
Låst
Good or bad?
Student robot Peter is an overachiever. Previously, his server was configured to receive scores on a five-point scale, but now his teachers have switched to a 12-point scale. But Peter doesn't know this. He's still focused on getting fives. Let's write him a compare method that compares any number with five.
4
Oppgave
Java Syntax,  nivålekse
Låst
Closest to 10
Ten is extremely popular and attractive number. Everyone wants to be a ten. Or at least as close to it as possible. Two numbers are standing around wondering which of them is cooler. Answer: whichever is closer to ten. Let's write these numbers a displayClosestToTen method that will determine which of them is cooler.
4
Oppgave
Java Syntax,  nivålekse
Låst
Come on, lucky seven!
Dice games are popular on the planet Foggy Multidimensions. The rules are different than the Earth version: Multidimensionals perceive far more dimensions than primitive three-dimensional earthlings. Their die has 4294967295 faces. Players win only if they roll a number between 50 and 100. We'll write a method that checks whether the die roll is in this range.
4
Oppgave
Java Syntax,  nivålekse
Låst
Seasons on Terra
An Earth year consists of four seasons, each of which lasts 3 months. While our ship was parked on this cradle of humanity, the Interplanetary Tax Service asked us to write a program to determine the season based on a number corresponding to the month of the year. We don't know why they want it. They say that it's none of our business. But they promised not to remain in our debt.
4
Oppgave
Java Syntax,  nivålekse
Låst
Positive and negative numbers
Diego is tall, but Alfredo is short. Rishi is experienced, but you're a "noob" programmer. Comparisons are unavoidable in life. And the same thing is true in programs. So we'll continue practicing comparisons and displaying stuff on the screen. This time let's compare the entered number with zero and manipulate it based on the result of the comparison.
4
Oppgave
Java Syntax,  nivålekse
Låst
Day of the week
Planet Terra still has "offices"—an outdated type of workspace. With current technology, there is no need for them, but earthlings tend to be nostalgic and haven't been in a hurry to eradicate them. Terrestrial office workers develop "TGIF syndrome": they constantly want to know what day of the week it is. Let's write a program for them!

En forelesningsbit med en mentor som en del av Codegym University-kurset. Meld deg på hele kurset.