C++ How to change a character to another one?

Question

C++ / C#

How to change a character in a certain place to another one?
#include
#include
using namespace std;
int main() {
char a[]="mad";
a[2]="n";
cout << a;
}

Answer 1

a[2]='n';
In double quotes, it is a null-terminated string, even if it contains 1 character. In single quotes, a character.