C++/Data Type/Char

cin and cout work with char array

<source lang="cpp">

1. include <iostream>

using namespace std; int main () {

  char name[ 80] = {"J", "e", "f", "f", "/0" };
  cout << "Enter your name: ";
  cin >> name;
  cout << "Your name is " << name;
  return 0;

}

 </source>

Convert a number to a char then convert to upper case and lower case

<source lang="cpp">

1. include <iostream>

using namespace std; int main() {

 char a,u,l;
 int x;
 cout << "Please enter a number \n";
 cin >> a;
 x = atoi(&a);
 cout << "The character " << a << " is converted to the integer " << x << "\n";
 cout << "Please enter a character \n";
 cin >> a;
 u = toupper(a);
 l = tolower(a);

 cout << a << " in upper case is " << u << " in lower case is " << l;
 return 0;

}

 </source>

Declare a stack class for characters.

<source lang="cpp">

1. include <iostream>

using namespace std;

1. define SIZE 10

class stack {

 char stackData[SIZE];        // holds the stack
 int topOfStack;              // index of top-of-stack

public:

 stack() { topOfStack = 0; }
 void push(char ch)
 {
   if(topOfStack==SIZE) {
     cout << "Stack is full\n";
     return;
   }
   stackData[topOfStack] = ch;
   topOfStack++;
 }
 char pop()
 {
   if(topOfStack==0) {
     cout << "Stack is empty\n";
     return 0;                // return null on empty stack 
   }
   topOfStack--;
   return stackData[topOfStack];
 }

}; int main() {

 stack stackObject1, stackObject2; 
 int i;
 stackObject1.push("a");
 stackObject2.push("x");
 stackObject1.push("b");
 stackObject2.push("y");
 stackObject1.push("c");
 stackObject2.push("z");
 for(i = 0; i <3; i++) 
    cout << "Pop stackObject1: " << stackObject1.pop() << endl;
 for(i = 0; i <3; i++) 
    cout << "Pop stackObject2: " << stackObject2.pop() << endl;
 return 0;

}

 </source>

Declares str just before it is needed

<source lang="cpp">

1. include <iostream>

using namespace std; int main() {

 float f;
 double d;
 cout << "Enter two floating point numbers: ";
 cin >> f >> d;
 cout << "Enter a string: ";
 char str[80];  
 cin >> str;
 cout << f << " " << d << " " << str;
 return 0;

}

 </source>

Enters a character and outputs its octal, decimal, and hexadecimal code.

<source lang="cpp">

1. include <iostream>
2. include <iomanip>

1. include <string>

using namespace std; int main() {

  int number = " ";
  cout << "The white space code is:" << number << "." << endl;
  char ch;
  string prompt = "Please enter a character followed by <return>: ";
  cout << prompt;
  cin >> ch;                                         
  number = ch;
  cout << "The character " << ch << " has code" << number << endl;
  cout << uppercase                                  // For hex-digits
       << "     octal  decimal  hexadecimal\n "
       << oct << setw(8) << number
       << dec << setw(8) << number
       << hex << setw(8) << number << endl;
  return 0;

}

 </source>

Overload string reversal function.

<source lang="cpp">

1. include <iostream>
2. include <cstring>

using namespace std;

void reverseString(char *s); // reverse string in place void reverseString(char *in, char *out); // put reversal into out int main() {

 char s1[80], s2[80];
 strcpy(s1, "This is a test");
 reverseString(s1, s2);
 cout << s2 << endl;
 reverseString(s1);
 cout << s1 << endl;
 return 0;

} // Reverse string, put result in s. void reverseString(char *s) {

 char temp[80];
 int i, j;
 for(i=strlen(s)-1, j=0; i>=0; i--, j++)
   temp[j] = s[ i ];
 temp[j] = "\0"; // null terminate result
 strcpy(s, temp);

} // Reverse string, put result into out. void reverseString(char *in, char *out) {

 int i, j;
 for(i=strlen(in)-1, j=0; i>=0; i--, j++)
   out[j] = in[ i ];
 out[j] = "\0"; // null terminate result

}

 </source>

Read string and output its length

<source lang="cpp">

1. include <iostream>
2. include <cstring>

using namespace std; int main() {

 char s[80];
 
 cout << "Enter a string: ";
 cin >> s;
 cout << "Length: " << strlen(s) << endl;
 return 0;

}

 </source>

Using C strings: cin,=.sync, getline

<source lang="cpp">

1. include <iostream>
2. include <iomanip>
3. include <cstring>

using namespace std; char header[] = "C Strings\n"; int main() {

  char hello[30] = "Hello ", name[20], message[80];
  cout << header << "Your first name: ";
  cin  >> setw(20) >> name;   
  strcat( hello, name);       
  cout << hello << endl;
  cin.sync();                 
  cout << "\nWhat is the message for today?"
       << endl;
  cin.getline( message, 80); 
  if( strlen( message) > 0) {                           
    for( int i=0; message[i] != "\0"; ++i)
      cout << message[i] << " ";   
    cout << endl;                  
  }
  return 0;

}

 </source>

Using functions isdigit, isalpha, isalnum, and isxdigit

<source lang="cpp">

1. include <iostream>
2. include <ctype.h>

using namespace std; int main() {

  cout << "According to isdigit:\n"
       << ( isdigit( "8" ) ? "8 is a" : "8 is not a" ) 
       << " digit\n"
       << ( isdigit( "#" ) ? "# is a" : "# is not a" ) 
       << " digit\n";
  cout << "\nAccording to isalpha:\n"
       << ( isalpha( "A" ) ? "A is a" : "A is not a" ) 
       << " letter\n"
       << ( isalpha( "b" ) ? "b is a" : "b is not a" ) 
       << " letter\n"
       << ( isalpha( "&" ) ? "& is a" : "& is not a" ) 
       << " letter\n"
       << ( isalpha( "4" ) ? "4 is a" : "4 is not a" ) 
       << " letter\n";
  cout << "\nAccording to isalnum:\n"
       << ( isalnum( "A" ) ? "A is a" : "A is not a" )
       << " digit or a letter\n"
       << ( isalnum( "8" ) ? "8 is a" : "8 is not a" )
       << " digit or a letter\n"
       << ( isalnum( "#" ) ? "# is a" : "# is not a" )
       << " digit or a letter\n";
  cout << "\nAccording to isxdigit:\n"
       << ( isxdigit( "F" ) ? "F is a" : "F is not a" )
       << " hexadecimal digit\n"
       << ( isxdigit( "J" ) ? "J is a" : "J is not a" )
       << " hexadecimal digit\n"
       << ( isxdigit( "7" ) ? "7 is a" : "7 is not a" )
       << " hexadecimal digit\n"
       << ( isxdigit( "$" ) ? "$ is a" : "$ is not a" )
       << " hexadecimal digit\n"
       << ( isxdigit( "f" ) ? "f is a" : "f is not a" )
       << " hexadecimal digit" << endl;
  return 0;

}

 </source>

Using functions islower, isupper, tolower, toupper

<source lang="cpp">

1. include <iostream>
2. include <ctype.h>

using namespace std; int main() {

  cout << "According to islower:\n"
       << ( islower( "p" ) ? "p is a" : "p is not a" ) 
       << " lowercase letter\n"
       << ( islower( "P" ) ? "P is a" : "P is not a" ) 
       << " lowercase letter\n"
       << ( islower( "5" ) ? "5 is a" : "5 is not a" ) 
       << " lowercase letter\n"
       << ( islower( "!" ) ? "! is a" : "! is not a" ) 
       << " lowercase letter\n";
  cout << "\nAccording to isupper:\n"
       << ( isupper( "D" ) ? "D is an" : "D is not an" ) 
       << " uppercase letter\n"
       << ( isupper( "d" ) ? "d is an" : "d is not an" ) 
       << " uppercase letter\n"
       << ( isupper( "8" ) ? "8 is an" : "8 is not an" ) 
       << " uppercase letter\n"
       << ( isupper("$") ? "$ is an" : "$ is not an" ) 
       << " uppercase letter\n";
  cout << "\nu converted to uppercase is " 
       << ( char ) toupper( "u" ) 
       << "\n7 converted to uppercase is " 
       << ( char ) toupper( "7" ) 
       << "\n$ converted to uppercase is " 
       << ( char ) toupper( "$" ) 
       << "\nL converted to lowercase is " 
       << ( char ) tolower( "L" ) << endl;
  return 0;

}

 </source>

Using functions isspace, iscntrl, ispunct, isprint, isgraph

<source lang="cpp">

1. include <iostream>
2. include <ctype.h>

using namespace std; int main(){

  cout << "According to isspace:\nNewline " 
       << ( isspace( "\n" ) ? "is a" : "is not a" )
       << " whitespace character\nHorizontal tab " 
       << ( isspace( "\t" ) ? "is a" : "is not a" )
       << " whitespace character\n"
       << ( isspace( "%" ) ? "% is a" : "% is not a" )
       << " whitespace character\n";
  cout << "\nAccording to iscntrl:\nNewline " 
       << ( iscntrl( "\n" ) ? "is a" : "is not a" )
       << " control character\n"
       << ( iscntrl( "$" ) ? "$ is a" : "$ is not a" )
       << " control character\n";
  cout << "\nAccording to ispunct:\n"
       << ( ispunct( ";" ) ? "; is a" : "; is not a" )
       << " punctuation character\n"
       << ( ispunct( "Y" ) ? "Y is a" : "Y is not a" )
       << " punctuation character\n"
       << ( ispunct("#") ? "# is a" : "# is not a" )
       << " punctuation character\n";
  cout << "\nAccording to isprint:\n"
       << ( isprint( "$" ) ? "$ is a" : "$ is not a" )
       << " printing character\nAlert " 
       << ( isprint( "\a" ) ? "is a" : "is not a" )
       << " printing character\n";
  cout << "\nAccording to isgraph:\n"
       << ( isgraph( "Q" ) ? "Q is a" : "Q is not a" )
       << " printing character other than a space\nSpace " 
       << ( isgraph(" ") ? "is a" : "is not a" )
       << " printing character other than a space" << endl;
  return 0;

}

 </source>

Wrap char pointer to a String class

<source lang="cpp">

1. include <iostream>
2. include <cstring>
3. include <cstdlib>

using namespace std; class StringClass {

 char *p;
 int len;

public:

 StringClass();
 StringClass(char *s, int l);
 char *getstring() {
    return p; 
 }
 int getlength() { 
    return len; 
 }

}; StringClass::StringClass() {

 p = new char [255];
 if(!p) {
   cout << "Allocation error\n";
   exit(1);
 }
 *p = "\0"; // null string 
 len = 255;

} StringClass::StringClass(char *s, int l) {

 if(strlen(s) >= l) {
   cout << "Allocating too little memory!\n";
   exit(1);
 }
 p = new char [l];
 if(!p) {
   cout << "Allocation error\n";
   exit(1);
 }
 strcpy(p, s);
 len = l;

} int main() {

 StringClass stringObject1;
 StringClass stringObject2("www.java2s.com", 100);
 cout << "stringObject1: " << stringObject1.getstring() << " - Length: ";
 cout << stringObject1.getlength() << "\n";
 cout << "stringObject2: " << stringObject2.getstring() << " - Length: ";
 cout << stringObject2.getlength() << "\n";
 return 0;

}

 </source>