Answer :
To assign the first element of an array with the value 99, you need to use the correct index for the first element. In most programming languages, including C++, arrays are zero-indexed. This means that the first element is accessed using index 0.
Let's look at the options provided:
1. `myVector[1] - 99;` - This uses the index 1, which actually refers to the second element of the array, not the first, and uses a subtraction operator, which is incorrect.
2. `myVector [tex]$\square=99$[/tex];` - This option isn't syntactically correct for assigning a value to an element. The symbol used is not a correct operator for assignment.
3. `myVector[0] = 99;` - This option correctly uses the index 0 to access the first element of the array and uses the assignment operator `=` to assign the value 99. This is the correct choice for assigning the array's first element with 99.
4. `myVector [-1] - 99;` - The index -1 is typically not used for accessing elements in a language like C++ as it uses zero-based indexing, and -1 would be an invalid position unless explicitly handled otherwise in certain languages like Python. It also incorrectly uses the subtraction operator.
Therefore, the correct way to assign the array's first element with 99 is using the statement:
```cpp
myVector[0] = 99;
```
This method ensures that you're targeting the first element and assigning the value 99 to it.
Let's look at the options provided:
1. `myVector[1] - 99;` - This uses the index 1, which actually refers to the second element of the array, not the first, and uses a subtraction operator, which is incorrect.
2. `myVector [tex]$\square=99$[/tex];` - This option isn't syntactically correct for assigning a value to an element. The symbol used is not a correct operator for assignment.
3. `myVector[0] = 99;` - This option correctly uses the index 0 to access the first element of the array and uses the assignment operator `=` to assign the value 99. This is the correct choice for assigning the array's first element with 99.
4. `myVector [-1] - 99;` - The index -1 is typically not used for accessing elements in a language like C++ as it uses zero-based indexing, and -1 would be an invalid position unless explicitly handled otherwise in certain languages like Python. It also incorrectly uses the subtraction operator.
Therefore, the correct way to assign the array's first element with 99 is using the statement:
```cpp
myVector[0] = 99;
```
This method ensures that you're targeting the first element and assigning the value 99 to it.
