String to Integer && Integer to String
(Don't use atoi() because it is for character array ; char s[] ="1234";)
string s ="1234";
int x = stoi (s);
float y = stof (s);
double z = stod (s);
Character to integer:
char ch = '8';
int num = ch - '0';
Integer to String :
int num = 123;
string s = to_string (num);
Integer to Character:
int num = 1;
char ch = num + '0';