// Arup Guha
// 9/19/2011
// Written in COP 3223 to illustrate loops.

#include <stdio.h>

const double TIP_RATE = 0.15;

int main() {

    // while counting backwards.
    int counter = 0;
    while (counter < 10){
        printf("%d. Hello World\n", 10 - counter);
        counter++;
    }

    // for adding each number from 1 to 100.
    int sum = 0;
    for (counter=1; counter<=100; counter++) {
        sum = sum + counter;
        printf("After day %d, you have %d dollars\n", counter, sum);
    }
    printf("You made %d dollars\n", sum);

    // Another for adding .01, .02, .04, .08, ... for 30 terms.
    double sum2 = 0;
    double payment = 0.01;
    for (counter = 1; counter<=30; counter++) {
        sum2 = sum2 + payment;
        payment = 2*payment;
    }
    printf("You made %.2lf dollars\n", sum2);

    // Prints out a tip chart for 15% with a minimum
    // tip of 2 dollars.
    int dollar;
    for (dollar=1; dollar<=100; dollar++) {

        double tip = dollar*TIP_RATE;
        if (tip < 2)
            tip = 2;

        printf("%d\t%.2lf\n", dollar, tip);
    }

    return 0;
}