The end result of three hours of work. This class is /boring/.

ex1.cpp

/* ex1.cpp
 * Author: Kye Russell
 * Date:   15/08/2011
 *
 * - Read in temperatures for every day in Jan (31).  Provide a prompt with a runnin
 *   day total.
 * - Print the averge of all temperatures:
 *   - >30    degrees.
 *   - 20-30  degrees.
 *   - <20    degrees.
 */
 
#include <iostream>

using namespace std;

int main() {
    /* Variable Declaration */
    float temp, lowtotal = 0, mediumtotal = 0, hightotal = 0;
    unsigned short lowcount = 0, mediumcount = 0, highcount = 0, totaldays = 31, day;
    
        /* Banner */
    cout << "ex1.cpp - Kye Russell" << endl;
    cout << "15/08/2011 - Central Institute of Technology." << endl;
    cout << "See the source code for instructions on use..." << endl << endl;
    
    cout << "Enter a temperature for day:" << endl;  //beginning of prompt.
    for (day = 1; day <= totaldays; day++) {  //loop through days
           cout << "\t" << day << " of " << totaldays << ":  ";  //prompt.
           cin >> temp;  //read in temperature.
           /* Calculate range that temp. belongs to.
            * Add current temp. to total of relevant range, and increment its counter.
            */
            
           if (temp < 20) {  //low range.
              lowcount++;
              lowtotal += temp;
           }else if (temp < 30) {  //medium range.
                 mediumcount++;
                 mediumtotal += temp;
           }else{  //high range.
                 highcount++;
                 hightotal += temp;
           }
    }
    
    
    /* Calculate the results.
     * For every range (low, medium, high) check for divide by zero errors.
     * If the division is valid, calculate the average.
     * If the division is invalid, print "no data" for the range.
     */
    cout << endl << "Averages:" << endl;
    
    /* Low Range */
    cout << "\tLow (below 20):  ";
    if (lowcount != 0) {
       cout << lowtotal / lowcount << endl;
    }else{
       cout << "No data." << endl;
    }
    
    /* Medium Range */
    cout << "\tMedium (20 to 30):  ";
    if (mediumcount != 0) {
       cout << mediumtotal / mediumcount << endl;
    }else{
       cout << "No data." << endl;
    }

    /* High Range */
    cout << "\tHigh (above 30):  ";
    if (highcount != 0) {
       cout << hightotal / highcount << endl;
    }else{
       cout << "No data." << endl;
    }
    
    system("pause");  //pause cli.
    return 0;
}   

ex2.cpp

/* ex2.cpp
 * Author: Kye Russell
 * Date:   15/08/2011
 *
 * Read in fuel consumption figures as floating point data until a negative value is read.
 * Print the total of:
 * - 'Good' cars (<7)
 * - 'Fair' cars (7-10)
 * - 'Poor' cars (>10)
 */
 
#include <iostream>

using namespace std;

int main() {
    /* Declare Variables */
    unsigned short goodcount = 0, faircount = 0, poorcount = 0;
    float consumption;
    
    /* Banner */
    cout << "ex2.cpp - Kye Russell" << endl;
    cout << "15/08/2011 - Central Institute of Technology." << endl;
    cout << "See the source code for instructions on use..." << endl << endl;
    
    /* Initial Prompt */
    cout << "Enter a consumption value: ";
    cin >> consumption;
    
    /* Enter the loop, starting with the value just obtained.
     * Add to relevant total. */
    while (consumption > 0) {  //loop until megative value received.
          if (consumption < 7) {  //good.
             goodcount++;
          }else if (consumption <= 10) {  //fair.
             faircount++;
          }else{  //poor.
             poorcount++;
          }
          
          /* Prompt for the next value */
          cout << "Enter another value: ";
          cin >> consumption;
    }
    
    /* Negative value received.  Print the results */
    cout << "Results:" << endl;
    cout << "\t'Good' (less than 7L/100km):\t" << goodcount << endl;
    cout << "\t'Fair' (between 7L-10L/100km):\t" << faircount << endl;
    cout << "\t'Poor' (over 10L/100km):\t" << poorcount << endl;
    
    system("pause");  //pause cli.
    return 0;
}   

ex3.cpp

/* ex3.cpp
 * Author: Kye Russell
 * Date:   15/08/2011
 *
 * Read in grades for 10 students.
 * - Validate grades (>0 AND <100).
 * - Print average of:
 *   - Students that passed (>=50)
 *   - Students that failed (<50)
 */
 
#include <iostream>

using namespace std;

int main() {
    /* Declare Variables */
    unsigned short passcount = 0, passtotal = 0, failcount = 0, failtotal = 0, student;
    signed short mark;
    
    /* Banner */
    cout << "ex3.cpp - Kye Russell" << endl;
    cout << "15/08/2011 - Central Institute of Technology." << endl;
    cout << "See the source code for instructions on use..." << endl << endl;

    /* Loop through the students */
    for (student = 1; student <= 10; student++) {
        do {
           cout << "Enter a mark (" << student << "/10): ";  //prompt
           cin >> mark;
        }while (mark < 0 || mark > 100);  //prompt until we get a valid result.
        
        if (mark >= 50) {  //check if result is pass.
           passcount++;  //it is, increment counter.
           passtotal += mark;  //and add to total;
        }else{
           failcount++;  //it isn't, increment fail counter.
           failtotal += mark; //and add to total.
        }
    }

    /* Print Results
     * Calculate average of pass/fail grades.  Do divide-by-zero checking.
     */
    cout << "Results:" << endl;
    
    cout << "\tPass: " ;
    if (passtotal != 0) {  //won't 0/0
       cout << passtotal / passcount;
    }else{  //no marks for the range.
       cout << "No data.";
    }
    cout << endl;
    
    cout << "\tFail: ";
    if (failcount != 0) {  //won't 0/0
       cout << failtotal / failcount;
    }else{  //no marks for the range.
       cout << "No data.";
    }
    cout << endl;
    
    system("pause");  //pause cli.
    return 0;
}