Programming Projects in Chapter 2

1.

#include <stdio.h>
int main(void)
{
        printf("        *\n");
        printf("       *\n");
        printf("      *\n");
        printf("     *\n");
        printf("*   *\n");
        printf(" * *\n");
        printf("  *\n");
        return 0;
}

2.

#include <stdio.h>
#define _USE_MATH_DEFINES
#include <math.h>
int main(void)
{
        printf("%f\n", (4.0f/3.0f)*M_PI*pow(10,3));
        return 0;
}
 

3.

#include <stdio.h>
#define _USE_MATH_DEFINES
#include <math.h>
int main(void)
{
        int radius;
        printf("Hello, Enter yours: ");
        scanf("%d", &radius);
        
        printf("%f\n", (4.0f/3.0f)*M_PI*pow(radius,3));
        return 0;
}
 

4.

#include <stdio.h>
int main(void)
{
        float dollar;
        printf("Enter and amount: ");
        scanf("%f", &dollar);
        printf("With tax added: $%.2f\n", dollar*21/20); //세금 붙은 가격출력
        return 0;
}
 

5.

#include <stdio.h>
int main(void)
{
        int x;
        scanf("%d", &x);
        printf("%d\n", (3*x*x*x*x*x)+(2*x*x*x*x)-(5*x*x*x)-(1*x*x)+(7*x)-6);
        return 0;
}
 

6.  Horner's Rule

#include <stdio.h>
int main(void)
{
        int x;
        scanf("%d", &x);
        printf("%d\n", ((((3*x+2)*x-5)*x-1)*x+7)*x-6);
        return 0;
}
 

7.

#include <stdio.h>
int main(void)
{
    int amt;
    int bill_20, bill_10, bill_5, bill_1;
    printf("Enter a dollar amount: ");
    scanf("%d", &amt);
    bill_20 = amt / 20;   
    bill_10 = (amt % 20) / 10; 
    bill_5 = (amt % 10) / 5; 
    bill_1 = amt % 5; 
    printf("$20 bills: %d\n", bill_20);
    printf("$10 bills: %d\n", bill_10);
    printf(" $5 bills: %d\n", bill_5);
    printf(" $1 bills: %d\n", bill_1);
    return 0;
}
 

8. 

※ 실수형의 Rounding 때문인지 값이 실제 책에 있는 정답과는 다르다.

#include <stdio.h>
int main(void)
{
        double loan, rate, payment, mir;
        printf("Enter amount of loan: ");
        scanf("%lf", &loan);
        printf("Enter interest rate: ");
        scanf("%lf", &rate);
        printf("Enter monthly payment: ");
        scanf("%lf", &payment);
        mir = (rate / 100) / 12;
        printf("Balance remaining after first payment: $%.2lf\n", loan - payment + loan * mir);
        printf("Balance remaining after second payment: $%.2lf\n", loan - payment*2 + loan * mir*2);
        printf("Balance remaining after third payment: $%.2lf\n", loan - payment*3 + loan * mir*3);
        return 0;
}