//ex02_08.cpp
// raise x to the y power
#include <iostream>

using std::cout;
using std::cin;
using std::endl;

int main()
{
   int x, y, i, power;

   i = 1;
   power = 1;

   cout << "Enter base as an integer: ";
   cin >> x;

   cout << "Enter exponent as an integer: ";
   cin >> y;

   while ( i <= y ) {
      power *= x;
      ++i;
   }

   cout << power << endl;
   return 0;
}

//ex02_15.cpp
#include <iostream>

using std::cout;
using std::endl;

int main()
{
   int y, x = 1, total = 0;

   while ( x <= 10 ) {
      y = x * x;
      cout << y << endl;
      total += y;
      ++x;
   }

   cout << "Total is " << total << endl;
   return 0;
}

//ex02_24.cpp
#include <iostream>

using std::cout;
using std::endl;

int main()
{
   int count = 1;

   while ( count <= 10 ) {
      cout << (count % 2 ? "****" : "++++++++")
           << endl;
      ++count;
   }

   return 0;
}

//ex02_25.cpp
#include <iostream>

using std::cout;
using std::endl;

int main()
{
   int row = 10, column;

   while ( row >= 1 ) {
      column = 1;

      while ( column <= 10 ) {
         cout << (row % 2 ? "<" : ">");
         ++column;
      }

      --row;
      cout << endl;
   }

   return 0;
}

//ex02_42.cpp
#include <iostream>

using std::cout;
using std::cin;
using std::endl;

int main()
{
   int x, y;

   cout << "Enter two integers in the range 1-20: ";
   cin >> x >> y;

   for ( int i = 1; i <= y; i++ ) {

      for ( int j = 1; j <= x; j++ )
         cout << '@';

      cout << endl;
   }

   return 0;
}

// Fig. 2.7: fig02_07.cpp
// Class average program with counter-controlled repetition
#include <iostream>

using std::cout;
using std::cin;
using std::endl;

int main()
{
   int total,        // sum of grades
       gradeCounter, // number of grades entered
       grade,        // one grade
       average;      // average of grades

   // initialization phase
   total = 0;                           // clear total
   gradeCounter = 1;                    // prepare to loop

   // processing phase
   while ( gradeCounter <= 10 ) {       // loop 10 times
      cout << "Enter grade: ";          // prompt for input
      cin >> grade;                     // input grade
      total = total + grade;            // add grade to total
      gradeCounter = gradeCounter + 1;  // increment counter
   }

   // termination phase
   average = total / 10;                // integer division
   cout << "Class average is " << average << endl;

   return 0;   // indicate program ended successfully
}  

// Fig. 2.9: fig02_09.cpp
// Class average program with sentinel-controlled repetition.
#include <iostream>

using std::cout;
using std::cin;
using std::endl;
using std::ios;

#include <iomanip>

using std::setprecision;
using std::setiosflags;

int main()
{
   int total,        // sum of grades
       gradeCounter, // number of grades entered
       grade;        // one grade
   double average;   // number with decimal point for average

   // initialization phase
   total = 0;
   gradeCounter = 0;

   // processing phase
   cout << "Enter grade, -1 to end: ";
   cin >> grade;

   while ( grade != -1 ) {
      total = total + grade;
      gradeCounter = gradeCounter + 1;
      cout << "Enter grade, -1 to end: ";
      cin >> grade;
   }

   // termination phase
   if ( gradeCounter != 0 ) {
      average = static_cast< double >( total ) / gradeCounter;
      cout << "Class average is " << setprecision( 2 )
           << setiosflags( ios::fixed | ios::showpoint )
           << average << endl;
   }
   else
      cout << "No grades were entered" << endl;

   return 0;   // indicate program ended successfully
}  

// Fig. 2.11: fig02_11.cpp
// Analysis of examination results
#include <iostream>

using std::cout;
using std::cin;
using std::endl;

int main()
{
   // initialize variables in declarations
   int passes = 0,           // number of passes
       failures = 0,         // number of failures
       studentCounter = 1,   // student counter
       result;               // one exam result

   // process 10 students; counter-controlled loop
   while ( studentCounter <= 10 ) {
      cout << "Enter result (1=pass,2=fail): ";
      cin >> result;

      if ( result == 1 )        // if/else nested in while
         passes = passes + 1;
      else
         failures = failures + 1;

      studentCounter = studentCounter + 1;
   }

   // termination phase
   cout << "Passed " << passes << endl;
   cout << "Failed " << failures << endl;

   if ( passes > 8 )
      cout << "Raise tuition " << endl;

   return 0;   // successful termination
}  

// Fig. 2.14: fig02_14.cpp
// Preincrementing and postincrementing
#include <iostream>

using std::cout;
using std::endl;

int main()
{
   int c;

   c = 5;
   cout << c << endl;         // print 5
   cout << c++ << endl;       // print 5 then postincrement
   cout << c << endl << endl; // print 6

   c = 5;
   cout << c << endl;         // print 5
   cout << ++c << endl;       // preincrement then print 6
   cout << c << endl;         // print 6

   return 0;                  // successful termination
}

// Fig. 2.16: fig02_16.cpp
// Counter-controlled repetition
#include <iostream>

using std::cout;
using std::endl;

int main()
{
   int counter = 1;             // initialization

   while ( counter <= 10 ) {    // repetition condition
      cout << counter << endl;
      ++counter;                // increment
   }

   return 0;
}

// Fig. 2.17: fig02_17.cpp
// Counter-controlled repetition with the for structure
#include <iostream>

using std::cout;
using std::endl;

int main()
{
   // Initialization, repetition condition, and incrementing
   // are all included in the for structure header.

   for ( int counter = 1; counter <= 10; counter++ )
      cout << counter << endl;

   return 0;
}

// Fig. 2.20: fig02_20.cpp
// Summation with for
#include <iostream>

using std::cout;
using std::endl;

int main()
{
   int sum = 0;

   for ( int number = 2; number <= 100; number += 2 )
      sum += number;

   cout << "Sum is " << sum << endl;

   return 0;
}

// Fig. 2.21: fig02_21.cpp
// Calculating compound interest
#include <iostream>

using std::cout;
using std::endl;
using std::ios;

#include <iomanip>

using std::setw;
using std::setiosflags;
using std::setprecision;

#include <cmath>

int main()
{
   double amount,              // amount on deposit
          principal = 1000.0,  // starting principal
          rate = .05;          // interest rate

   cout << "Year" << setw( 21 )
        << "Amount on deposit" << endl;

   // set the floating-point number format
   cout << setiosflags( ios::fixed | ios::showpoint )
        << setprecision( 2 );

   for ( int year = 1; year <= 10; year++ ) {
      amount = principal * pow( 1.0 + rate, year );
      cout << setw( 4 ) << year << setw( 21 ) << amount << endl;
   }

   return 0;
}

// Fig. 2.22: fig02_22.cpp
// Counting letter grades
#include <iostream>

using std::cout;
using std::cin;
using std::endl;

int main()
{
   int grade,       // one grade
       aCount = 0,  // number of A's
       bCount = 0,  // number of B's
       cCount = 0,  // number of C's
       dCount = 0,  // number of D's
       fCount = 0;  // number of F's

   cout << "Enter the letter grades." << endl
        << "Enter the EOF character to end input." << endl;

   while ( ( grade = cin.get() ) != EOF ) {

      switch ( grade ) {      // switch nested in while

         case 'A':  // grade was uppercase A
         case 'a':  // or lowercase a
            ++aCount;
            break;  // necessary to exit switch

         case 'B':  // grade was uppercase B
         case 'b':  // or lowercase b
            ++bCount;
            break;

         case 'C':  // grade was uppercase C
         case 'c':  // or lowercase c
            ++cCount;
            break;

         case 'D':  // grade was uppercase D
         case 'd':  // or lowercase d
            ++dCount;
            break;

         case 'F':  // grade was uppercase F
         case 'f':  // or lowercase f
            ++fCount;
            break;

         case '\n': // ignore newlines,
         case '\t': // tabs,
         case ' ':  // and spaces in input
            break;

         default:   // catch all other characters
            cout << "Incorrect letter grade entered."
                 << " Enter a new grade." << endl;
            break;  // optional
      }
   }

   cout << "\n\nTotals for each letter grade are:"
        << "\nA: " << aCount
        << "\nB: " << bCount
        << "\nC: " << cCount
        << "\nD: " << dCount
        << "\nF: " << fCount << endl;

   return 0;
}

// Fig. 2.24: fig02_24.cpp
// Using the do/while repetition structure
#include <iostream>

using std::cout;
using std::endl;

int main()
{
   int counter = 1;

   do {
      cout << counter << "  ";
   } while ( ++counter <= 10 );

   cout << endl;

   return 0;
}

// Fig. 2.26: fig02_26.cpp
// Using the break statement in a for structure
#include <iostream>

using std::cout;
using std::endl;

int main()
{
   // x declared here so it can be used after the loop
   int x;

   for ( x = 1; x <= 10; x++ ) {

      if ( x == 5 )
         break;    // break loop only if x is 5

      cout << x << " ";
   }

   cout << "\nBroke out of loop at x of " << x << endl;
   return 0;
}  

// Fig. 2.27: fig02_07.cpp
// Using the continue statement in a for structure
#include <iostream>

using std::cout;
using std::endl;

int main()
{
   for ( int x = 1; x <= 10; x++ ) {

      if ( x == 5 )
         continue;  // skip remaining code in loop
                    // only if x is 5

      cout << x << " ";
   }

   cout << "\nUsed continue to skip printing the value 5"
       << endl;
   return 0;
}