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法學在 Java 中的加法和連線
Java 中的“+”運算子既可用於新增數字，也可用於連線字串。應該考慮以下規則。
只有數字為運算元，結果將是數字。
只有字串為運算元，結果將是連線的字串。
如果數字和字串都是運算元，則在字串之前出現的數字將被視為數字。
如果數字和字串都是運算元，則在字串之後出現的數字將被視為字串。
可以用括號來覆蓋上述規則。
示例
建立一個名為 Tester 的 Java 類。
Tester.java
public class Tester {
public static void main(String args[]) {
//Scenario 1: Only numbers as operands to + operator
System.out.print("Scenario 1: (1 + 2) = ");
System.out.println(1 + 2);
//Scenario 2: Only Strings as operands to + operator
System.out.print("Scenario 2: (\"tutorials\" + \"point.com\") = ");
System.out.println("tutorials" + "points.com");
//Scenario 3: both numbers and strings as operands to + operator
//numbers will be treated as non-text till a string comes
System.out.print("Scenario 3: (1 + 2 + \"tutorials\" + \"point.com\") = ");
System.out.println( 1 + 2 + "tutorials" + "points.com");
//Scenario 4: both numbers and strings as operands to + operator
//if string comes first, numbers will be treated as text.
System.out.print("Scenario 4: (1 + 2 + \"tutorials\" + \"point.com\" + 3 + 4 ) = ");
System.out.println( 1 + 2 + "tutorials" + "points.com" + 3 + 4);
//Scenario 5: both numbers and strings as operands to + operator
//if string comes first, numbers will be treated as text.
//Use brackets to treat all numbers as non-text
System.out.print("Scenario 5: (1 + 2 + \"tutorials\" + \"point.com\" + (3 + 4)) = ");
System.out.println( 1 + 2 + "tutorials" + "points.com" + (3 + 4));
}
}輸出
編譯並執行檔案以驗證結果。
Scenario 1: (1 + 2) = 3
Scenario 2: ("tutorials" + "point.com") = tutorialspoints.com
Scenario 3: (1 + 2 + "tutorials" + "point.com") = 3tutorialspoints.com
Scenario 4: (1 + 2 + "tutorials" + "point.com" + 3 + 4 ) = 3tutorialspoints.com34
Scenario 5: (1 + 2 + "tutorials" + "point.com" + (3 + 4)) = 3tutorialspoints.com7
更新於：2020 年 6 月 18 日
1 千+ 次瀏覽
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