Input a string into an array and output the array string in uppercase

[Newbie318]

User inputs a string and the program outputs the string in uppercase letters.(Use Character array to store the string) This is what I came up with. I'm new to C++ and any help would be great.

#include <iostream>
#include <string>
using namespace std;
int main()
{
    int i;
    char a;
    char sequence[100];
    cout << "Enter a string of characters to convert to uppercase: ";
    
    for (i = 0; i < 100; i++)
    {
    cin >> sequence[a];
    cout << static_cast<char>(toupper(sequence[a]));
    }  
    system("pause");
    return 0;    
}

[weaknessforcats]

Using cin >> sequence[i] will be better. sequence[a] means nothing since the variable a is never initialized.

Also, you do not need the static_cast.