# [Java] First learning java #3 expressions and operators

## What is an expression?

```
public class Main {
public static void main(String[] args) {
int a;
int b;
a = 20;
b =a+5;
System.out.println(a);
System.out.println(b);
}
}
```

Execution result

```
20
twenty five
```

A thing like the sixth line is called an expression. “A”, “b”, and “5” are called operands, and “+” and “*” are called operators. As with any complex formula, all formulas consist of these two.

### literal

What is described in the source code such as “5” or “hello, world” among operants is called a literal. Literals have data types such as (int).

### Escape sequence

A special character is expressed by the notation method that is described by the yen symbol and the character following it.

Notation | Meaning |
---|---|

\” | Double quotation mark symbol |

¥ ′ | Quotation mark symbol |

\ | Yen sign |

\N | Line feed |

### operator

Operator | Function |
---|---|

+ | Addition |

ー | Subtraction |

* | Multiplication |

/ | Division |

% | Remainder of division (surplus) |

+ | Concatenation of strings |

= | Substitute right side for left side |

+= | Adds the left side and the right side and assigns to the left side (there is an arithmetic operator) |

++ | Increase value by one |

- —– | Decrement the value by one |