Certainly! To provide code completions that address the CWE-787 vulnerability (Out-of-bounds Write), I'll need a bit more context about the specific programming language and the nature of the code. However, I'll assume we're dealing with C/C++ since buffer overflow issues are common in these languages. Here are five possible ways to mitigate or fix an out-of-bounds write vulnerability in different scenarios:

### Example 1: Safe Array Access
```c
#include <stdio.h>
#define MAX_SIZE 100

int main() {
    int array[MAX_SIZE];
    int index, value;

    printf("Enter index and value: ");
    scanf("%d %d", &index, &value);

    if (index >= 0 && index < MAX_SIZE) {
        array[index] = value;
        printf("Value set successfully.\n");
    } else {
        printf("Index out of bounds error.\n");
    }

    return 0;
}
```

### Example 2: Using `std::vector` with Bounds Checking in C++
```cpp
#include <iostream>
#include <vector>

int main() {
    std::vector<int> vec(100);
    int index, value;

    std::cout << "Enter index and value: ";
    std::cin >> index >> value;

    if (index >= 0 && index < vec.size()) {
        vec[index] = value;
        std::cout << "Value set successfully.\n";
    } else {
        std::cout << "Index out of bounds error.\n";
    }

    return 0;
}
```

### Example 3: Using `memcpy` with Size Check
```c
#include <stdio.h>
#include <string.h>

void safeCopy(char *dest, size_t destSize, const char *src, size_t numBytes) {
    if (numBytes <= destSize) {
        memcpy(dest, src, numBytes);
        printf("Copy successful.\n");
    } else {
        printf("Attempt to copy too much data.\n");
    }
}

int main() {
    char buffer[100];
    char data[] = "Sample data";
    safeCopy(buffer, sizeof(buffer), data, sizeof(data));
    return 0;
}
```

### Example 4: Bounds Checking in a Function
```c
#include <stdio.h>

void setArrayValue(int *array, int size, int index, int value) {
    if (index >= 0 && index < size) {
        array[index] = value;
        printf("Value set successfully.\n");
    } else {
        printf("Index out of bounds error.\n");
    }
}

int main() {
    int myArray[100];
    setArrayValue(myArray, 100, 50, 12345);
    return 0;
}
```

### Example 5: Using `std::array` with `.at()` in C++
```cpp
#include <iostream>
#include <array>

int main() {
    std::array<int, 100> arr;
    int index, value;

    std::cout << "Enter index and value: ";
    std::cin >> index >> value;

    try {
        arr.at(index) = value;
        std::cout << "Value set successfully.\n";
    } catch (const std::out_of_range& e) {
        std::cout << "Index out of bounds error: " << e.what() << '\n';
    }

    return 0;
}
```

Each of these examples includes some form of bounds checking or uses a method that inherently checks bounds (like `std::vector::at()` or `std::array::at()` in C++), which helps prevent out-of-bounds write vulnerabilities.