std::cout << "Hello World!" << std::endl;

"Hello World!"

{'H','e','l','l','o',' ','W','o','r','l','d','!'}

char c = 'H';

char c1 = 'A'; // ok
char c2 = "A"; // error

std::cout << (int)'H' << std::endl;

72

'H' == 72

char a = 'H';
char b = 72;
 
if (a == b)
  std::cout << "Same" << std::endl;
else
  std::cout << "Oops..." << std::endl;

'H' == 72

char b = 'a' + 1;
// b is 'b'
 
char Z = 'A' + 25;
// Z is 'Z'
 
char one = '2' - 1;
// one is '1';

char s[6] = "Hello";

char s1[2] = "A"; // ok
char s2[2] = 'A'; // error

char s[6] = "Hello";

char s[6] = "Hello";

char s[6] = {'H','e','l','l','o','\0'};

char s1[6] = "Hello"; // ok
char s2[6] = {'H', 'e', 'l', 'l', 'o', 0}; // ok

char s[6] = "Hello"; // ok
s = "World"; // error
s = {'W', 'o', 'r', 'l', 'd', '\0'}; // error

char s[6] = "Hello";
std::cout << s << std::endl;

char a[5] = {'H', 'e', 'l', 'l', 'o'};
char b[6] = "World";
std::cout << a << std::endl;
std::cout << b << std::endl;

HelloWorld
World

Hello World

char s[100];
std::cin >> s;
std::cout << s << std::endl;

Hello

char s[100] = "Sprout";
std::cout << strlen(s) << std::endl;

6

char s[100] = "Sprout";
for (int i = 0; i < strlen(s); i++)
  std::cout << s[i] << std::endl;

char s[100] = "Sprout";
int len = strlen(s);
for (int i = 0; i < len; i++)
  std::cout << s[i] << std::endl;

char a[100] = "same";
char b[100] = "same";
if (strcmp(a, b) == 0) {
  std::cout << "same strings" << std::endl;
} else {
  std::cout << "different" << std::endl;
}

char a[100] = "old";
a = "new";

char a[100] = "old";
strcpy(a, "new");
// now a is "new"

char a[100] = "front";
a += "back"; // error

char a[100] = "front";
strcpy(a, "back");
// a is now "frontback"