java 标记“-”上的语法错误，无效的 AssignmentOperator
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Syntax error on token "-", invalid AssignmentOperator
提问by Riemke Shabadoo
for (int iI = 4; iI > 0; iI--)
faAmount[iI] - faAmount[iI - 1];
This is the code it's in. How can I fix this?
这是它所在的代码。我该如何解决这个问题？
回答by Luiggi Mendoza
Maybe you forgot the equal sign
也许你忘了等号
for (int iI = 4; iI > 0; iI--)
faAmount[iI] -= faAmount[iI - 1];
Or to assign the difference in a variable
或分配变量中的差异
double x = 0; //or another value
for (int iI = 4; iI > 0; iI--)
x = faAmount[iI] - faAmount[iI - 1];
回答by MByD
faAmount[iI] - faAmount[iI - 1]is n expression that have a result, but you don't assign it to anything, this is invalid in Java.
faAmount[iI] - faAmount[iI - 1]是有结果的 n 表达式，但你没有将它分配给任何东西，这在 Java 中是无效的。
回答by trutheality
The technical explanation is that faAmount[iI] - faAmount[iI - 1]is an expression but isn't a statement. The JLS notes that
技术上的解释是，这faAmount[iI] - faAmount[iI - 1]是一个表达式，而不是一个语句。JLS 指出
Unlike C and C++, the Java programming language allows only certain forms of expressions to be used as expression statements.
与 C 和 C++ 不同，Java 编程语言只允许将某些形式的表达式用作表达式语句。
An additive expression is not one of those expressions that are also statements.
加法表达式不是那些也是语句的表达式之一。
