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The concept that is important to understand here is the concept of operator precedence. Assume you have an expression a + b * c. What does it mean? You could have the following options: (a + b) ...
Answer
#3: Post edited
by
Dirk Herrmann
·
2022-05-01T11:27:12Z (over 2 years ago)
- The concept that is important to understand here is the concept of operator precedence.
- Assume you have an expression `a + b * c`. What does it mean? You could have the following options: `(a + b) * c` or `a + (b * c)`. By adding the parentheses it can be made clear what shall be computed first, but what without the parentheses?
In mathematics as well as in all programming languages that I am aware of that allow such expressions (some languages don't use this kind of syntax at all) the meaning of `a + b * c` is by convention `a + (b * c)`. This is because the `*` is defined to have a higher precedence than `+`. If of two operators one has higher precedence this means, that that one "wins" over the other when it comes to computation order. Since `*` has a higher precedence than the `+`, you first have to compute the `*` and afterwards the `+`.- Looking at the expression from the question: `(x == 42) * -1 + (x != 42) * x` thus means the same as `((x == 42) * -1) + ((x != 42) * x)`. Thus, when `x` has the value 42, this results in `(1 * -1) + (0 * x)` that is -1 + 0 which gives -1.
- The concept that is important to understand here is the concept of operator precedence.
- Assume you have an expression `a + b * c`. What does it mean? You could have the following options: `(a + b) * c` or `a + (b * c)`. By adding the parentheses it can be made clear what shall be computed first, but what without the parentheses?
- In mathematics as well as in all programming languages that I am aware of that allow such expressions (some languages don't use this kind of syntax at all) the meaning of `a + b * c` is `a + (b * c)`. This is because the `*` is commonly defined to have a higher precedence than `+`. If of two operators one has higher precedence this means, that that one "wins" over the other when it comes to computation order. Since `*` has a higher precedence than the `+`, you first have to compute the `*` and afterwards the `+`.
- Looking at the expression from the question: `(x == 42) * -1 + (x != 42) * x` thus means the same as `((x == 42) * -1) + ((x != 42) * x)`. Thus, when `x` has the value 42, this results in `(1 * -1) + (0 * x)` that is -1 + 0 which gives -1.
#2: Post edited
by
Dirk Herrmann
·
2022-05-01T11:26:19Z (over 2 years ago)
- The concept that is important to understand here is the concept of operator precedence.
- Assume you have an expression `a + b * c`. What does it mean? You could have the following options: `(a + b) * c` or `a + (b * c)`. By adding the parentheses it can be made clear what shall be computed first, but what without the parentheses?
In mathematics as well as in all programming languages that I am aware of that allow such expressions (some languages don't use this kind of syntax at all) the meaning of `a + b * c` is `a + (b * c)`. This is because the `*` has a higher precedence than `+`. If of two operators one has higher precedence this means, that that one "wins" over the other when it comes to computation order. Since `*` has a higher precedence than the `+`, you first have to compute the `*` and afterwards the `+`.- Looking at the expression from the question: `(x == 42) * -1 + (x != 42) * x` thus means the same as `((x == 42) * -1) + ((x != 42) * x)`. Thus, when `x` has the value 42, this results in `(1 * -1) + (0 * x)` that is -1 + 0 which gives -1.
- The concept that is important to understand here is the concept of operator precedence.
- Assume you have an expression `a + b * c`. What does it mean? You could have the following options: `(a + b) * c` or `a + (b * c)`. By adding the parentheses it can be made clear what shall be computed first, but what without the parentheses?
- In mathematics as well as in all programming languages that I am aware of that allow such expressions (some languages don't use this kind of syntax at all) the meaning of `a + b * c` is by convention `a + (b * c)`. This is because the `*` is defined to have a higher precedence than `+`. If of two operators one has higher precedence this means, that that one "wins" over the other when it comes to computation order. Since `*` has a higher precedence than the `+`, you first have to compute the `*` and afterwards the `+`.
- Looking at the expression from the question: `(x == 42) * -1 + (x != 42) * x` thus means the same as `((x == 42) * -1) + ((x != 42) * x)`. Thus, when `x` has the value 42, this results in `(1 * -1) + (0 * x)` that is -1 + 0 which gives -1.
#1: Initial revision
by
Dirk Herrmann
·
2022-05-01T11:20:09Z (over 2 years ago)
The concept that is important to understand here is the concept of operator precedence. Assume you have an expression `a + b * c`. What does it mean? You could have the following options: `(a + b) * c` or `a + (b * c)`. By adding the parentheses it can be made clear what shall be computed first, but what without the parentheses? In mathematics as well as in all programming languages that I am aware of that allow such expressions (some languages don't use this kind of syntax at all) the meaning of `a + b * c` is `a + (b * c)`. This is because the `*` has a higher precedence than `+`. If of two operators one has higher precedence this means, that that one "wins" over the other when it comes to computation order. Since `*` has a higher precedence than the `+`, you first have to compute the `*` and afterwards the `+`. Looking at the expression from the question: `(x == 42) * -1 + (x != 42) * x` thus means the same as `((x == 42) * -1) + ((x != 42) * x)`. Thus, when `x` has the value 42, this results in `(1 * -1) + (0 * x)` that is -1 + 0 which gives -1.