프로그래밍 공부노트

#include <stdio.h>

int main(void)

{

char ch;

int len = 0;

printf("Enter a message: ");

ch = getchar();

while (ch != '\n') {

len++;

ch = getchar();

}

printf("Your message was %d character(s) long.\n", len);

return 0;

}

#include <stdio.h>

int main(void)

{

int len = 0;

printf("Enter a message: ");

while (getchar() != '\n')

len++;

printf("Your message was %d charater(s) long.\n", len);

return 0;

}

#pragma warning(disable:4996)

#include <stdio.h>

/* Balances a Checkbook */

int main(void)

{

int cmd;

float balance = 0.0f, credit, debit;

printf("*** ACME checkbook-balancing program ***\n");

printf("Commands: 0=clear, 1=credit, 2=debit, ");

printf("3=balance, 4=exit\n\n");

for (;;) {

printf("Enter command: ");

scanf("%d", &cmd);

switch (cmd) {

case 0:

balance = 0.0f;

break;

case 1:

printf("Enter amount of credit: ");

scanf("%f", &credit);

balance += credit;

break;

case 2:

printf("Enter amount of debit: ");

scanf("%f", &debit);

balance -= debit;

break;

case 3:

printf("Current balance: $%.2f\n", balance);

break;

case 4:

return 0;

default:

printf("Commands: 0=clear, 1=credit, 2=debit, ");

printf("3=balance, 4=exit\n\n");

break;

}

}

}

#pragma warning(disable:4996)

#include <stdio.h>

int main(void)

{

int d, n;

printf("input n: ");

scanf("%d", &n);

for (d = 2; d < n && n%d != 0; d++);

if (d < n)

printf("%d is divisible by %d\n", n, d);

else

printf("%d is a prime number.\n", n);

}

exercises

4번

(a) for (i=0; i<10; i++)

(b) for (i=0; i<10; ++i)

(c) for (i=0; i++<10;)

중 다른 하나는 (c). loop body가 실행되기 전에 i가 1 증가하기 때문이다.

6번

for (int i = 1; i <= 128; i *= 2)

printf("%d ", i);

12번 조금 더 효율적으로 소수 구하기(n의 sqrt까지만 for 문 돌리기)

#pragma warning(disable:4996)

#include <stdio.h>

int main(void)

{

int d, n;

printf("input value of n: ");

scanf("%d", &n);

for (d = 2; d*d < n; d++)

if (n % d == 0)

{

printf("%d is divisible by %d.\n", n, d);

return 0;

}

printf("%d is a prime number.\n", n);

}

Projects

1번

#pragma warning(disable:4996)

#include <stdio.h>

int main(void)

{

float max, n;

n = 1, max = -1;

while (n > 0) {

printf("Enter a number: ");

scanf("%f", &n);

if (n > max)

max = n;

}

if (max >= 0)

printf("The largest number entered was %.2f\n", max);

else

printf("There is no nonnegative number entered.\n");

return 0;

}

2번 computing GCD(greatest common divisor)

#pragma warning(disable:4996)

#include <stdio.h>

int main(void)

{

int m, n, temp;

printf("Enter two integers: ");

scanf("%d %d", &m, &n);

for (; n > 0; temp = m%n, m = n, n = temp);

printf("Greatest common divisor: %d\n", m);

return 0;

}

3번 분수의 약분 - 분자와 분모의 최대공약수를 이용.

#pragma warning(disable:4996)

#include <stdio.h>

int main(void)

{

int m, n, temp, a, b;

printf("Enter a fraction: ");

scanf("%d/%d", &m, &n);

a = m, b = n;

for (; n > 0; temp = m%n, m = n, n = temp);

printf("Greatest common divisor: %d/%d\n", a/m, b/m);

return 0;

}

4번

#pragma warning(disable:4996)

#include <stdio.h>

int main()

{

float commission, value;

for (;;) {

printf("Enter value of trade: ");

scanf("%f", &value);

if (value == 0)

break;

if (value < 2500.00f)

commission = 30.00f + .017f * value;

else if (value < 6250.00f)

commission = 56.00f + .0066f * value;

else if (value < 20000.00f)

commission = 76.00f + .0034f * value;

else if (value < 50000.00f)

commission = 100.00f + .0022f * value;

else if (value < 500000.00f)

commission = 155.00f + .0011f * value;

else

commission = 255.00f + .0009f * value;

if (commission < 39.00f)

commission = 39.00f;

printf("Comission: %.2f\n", commission);

}

return 0;

}

5번

#pragma warning(disable:4996)

#include <stdio.h>

int main()

{

int i;

printf("Enter a number: ");

scanf("%d", &i);

printf("Reversed number is ");

do {

printf("%d", i % 10);

i /= 10;

} while (i > 0);

printf("\n");

return 0;

}

6번 even squares

#pragma warning(disable:4996)

#include <stdio.h>

int main()

{

int i, n;

printf("Enter a number: ");

scanf("%d", &n);

for (i = 2; i * i <= n; i+=2)

printf("%d\n", i*i);

return 0;

}

7번

// loop body를 for문의 괄호 안에 집어넣으려면, 기존 expr3 앞에다 집어넣기

#pragma warning(disable:4996)

#include <stdio.h>

int main(void)

{

int i, n, odd, square;

printf("This program prints a table of squares.\n");

printf("Enter number of entries in table: ");

scanf("%d", &n);

for (i = 1, odd = 3, square = 1; i <= n; ++i, square += odd, odd += 2) {

printf("%10d%10d\n", i, square);

}

return 0;

}

8번 그 달이 며칠인지와 1일이 어떤 요일인지 입력받아 달력 만들기

#pragma warning(disable:4996)

#include <stdio.h>

int main(void)

{

int i, n, start;

printf("Enter number of days in month: ");

scanf("%d", &n);

printf("Enter starting day of the week (1=Sun, 7=Sat): ");

scanf("%d", &start);

printf("\n Sun Mon Tue Wed Thu Fri Sat\n");

for (i = 1; i < start; i++)  // prints empty space before 1st

printf("    ");

for (i = 1; i <= n; i++)

{

printf("%4d", i);

if ((i + start - 1) % 7 == 0) printf("\n");

}

printf("\n\n");

return 0;

}

9번 chapter 2 project 8 monthly payment를 for문으로 표현하기

#pragma warning(disable:4996)

#include <stdio.h>

int main(void)

{

float total, ir, monthly;

int m; // number of payments before calculating balance remaining

printf("Enter amount of loan: ");

scanf("%f", &total);

printf("Enter interest rate: ");  // interest rate: 5% --> input 5

scanf("%f", &ir);

printf("Enter monthly payment: ");

scanf("%f", &monthly);

printf("Enter number of payment: ");

scanf("%d", &m);

for (int i = 1; i <= m; i++)

{

total = total * (1 + ir / 1200) - monthly;

printf("Balance remaining after payment %d: %.2f\n", i, total);

}

return 0;

}

10번 Chapter 5 project 9 더 빠른 날짜 구하기

#pragma warning(disable:4996)

#include <stdio.h>

int main()

{

int m1, d1, y1, m2, d2, y2, m0, d0, y0;

int compare; // -1: first date is earlier, 0: two dates are same, 1: second date is earlier

printf("연도 2자리 앞에 생략된 수는 20으로 간주함\n");

printf("Enter a date (mm/dd/yy): ");

scanf("%d/%d/%d", &m1, &d1, &y1);

for (;;) {

printf("Enter a date (mm/dd/yy): ");

scanf("%d/%d/%d", &m0, &d0, &y0);

if ((m0 == 0) && (d0 == 0) && (y0 == 0))

break;

else

m2 = m0, d2 = d0, y2 = y0;

if (y1 < y2)

compare = -1;

else if (y1 == y2)

{

if (m1 < m2)

compare = -1;

else if (m1 == m2)

{

if (d1 < d2)

compare = -1;

else if (d1 == d2)

compare = 0;

else

compare = 1;

}

else compare = 1;

}

else

compare = 1;

}

switch (compare)

{

case -1: case 0:

printf("%d/%d/%.2d is earliest date\n", m1, d1, y1);

break;

case 1:

printf("%d/%d/%.2d is earliest date\n", m2, d2, y2);

break;

}

return 0;

}

11번 e의 근사값 구하기

#pragma warning(disable:4996)

#include <stdio.h>

int main()

{

int i, n;

float fac, sum;

fac = 1, sum = 1;

printf("Enter a positive integeer: ");

scanf("%d", &n);

for (i = 1; i <= n; i++)

{

fac *= i;

sum += 1 / fac;

printf("%f\n", sum);

}

return 0;

}

12번

#pragma warning(disable:4996)

#include <stdio.h>

int main()

{

int i;

float fac, sum, eps;

fac = 1, sum = 1;

printf("Enter a small floating number: ");

scanf("%f", &eps);

for (i = 1; 1/fac >= eps; i++)

{

fac *= i;

sum += 1 / fac;

printf("%f\n", sum);

}

return 0;

}

#include <stdio.h>

int main()

{

float commission, value;

printf("Enter value of trade: ");

scanf("%f", &value);

if (value < 2500.00f)

commission = 30.00f + .017f * value;

else if (value < 6250.00f)

commission = 56.00f + .0066f * value;

else if (value < 20000.00f)

commission = 76.00f + .0034f * value;

else if (value < 50000.00f)

commission = 100.00f + .0022f * value;

else if (value < 500000.00f)

commission = 155.00f + .0011f * value;

else

commission = 255.00f + .0009f * value;

if (commission < 39.00f)

commission = 39.00f;

printf("Comission: %.2f\n", commission);

return 0;

}

#pragma warning(disable:4996)

#include <stdio.h>

int main()

{

int month, day, year;

printf("Enter date (mm/dd/yy): ");

scanf("%d/%d/%d", &month, &day, &year);

printf("Dated this %d", day);

switch (day) {

case 1: case 21: case 31:

printf("st"); break;

case 2: case 22:

printf("nd"); break;

case 3: case 23:

printf("rd"); break;

default: printf("th"); break;

}

printf(" day of ");

switch (month) {

case 1: printf("January"); break;

case 2: printf("February"); break;

case 3: printf("March");          break;

case 4: printf("April");         break;

case 5: printf("May"); break;

case 6: printf("June"); break;

case 7: printf("July"); break;

case 8: printf("August"); break;

case 9: printf("September");     break;

case 10: printf("October"); break;

case 11: printf("November");     break;

case 12: printf("December");         break;

}

printf(", 20%.2d.\n", year);

return 0;

}

exercieses 

4번 i<j이면 -1, i=j이면 0, i>j면 1을 반환하는 single expression

(i>j) - (i<j)

8번 변수에 true or false값을 하나의 assignment로 집어넣기

#include <stdio.h>

#include <stdbool.h>

int main()

{

int age;

bool teenager;

teenager = (age >= 13 && age <= 19);

}

11번 Area code

switch (area_code) {

case 229: 

printf("Albany"); break;

case 404: case 470: case 678: case 770:

printf("Atlanta");  break;

case 478:

printf("Macon"); break;

case 706: case 762:

printf("Columbus"); break;

case 912:

printf("Savannah"); break;

default:

printf("Area code not recognized");

}

projects

1번

#pragma warning(disable:4996)

#include <stdio.h>

int main()

{

int i, j;

printf("Enter a number: ");

scanf("%d", &i);

if (i >= 0 && i <= 9)

j = 1;

else if (i >= 10 && i <= 99)

j = 2;

else if (i >= 100 && i <= 999)

j = 3;

else if (i >= 1000 && i <= 9999)

j = 4;

else

{

printf("Invalid input.\n");

exit(1);

}

printf("The number %d has %d digits.\n", i, j);

}

2번

#pragma warning(disable:4996)

#include <stdio.h>

int main()

{

int h, m;

printf("Enter a 24-hour time: ");

scanf("%d:%d", &h, &m);

printf("Equivalent 12-hour time: ");

if (h == 0)

printf("12:%.2d AM\n", m);

else if (0 < h && h <= 11)

printf("%d:%.2d AM\n", h, m);

else if

(13 <= h && h <= 23)

printf("%d:%.2d PM\n", h - 12, m);

else  // h = 12

printf("%d:%.2d PM\n", h, m);

return 0;

}

3번

#pragma warning(disable:4996)

#include <stdio.h>

int main()

{

float commission, price, value;

int shares;

float commission_rival;

printf("Enter the number of shares: ");

scanf("%d", &shares);

printf("Enter the price per share: ");

scanf("%f", &price);

value = shares * price;

if (value < 2500.00f)

commission = 30.00f + .017f * value;

else if (value < 6250.00f)

commission = 56.00f + .0066f * value;

else if (value < 20000.00f)

commission = 76.00f + .0034f * value;

else if (value < 50000.00f)

commission = 100.00f + .0022f * value;

else if (value < 500000.00f)

commission = 155.00f + .0011f * value;

else

commission = 255.00f + .0009f * value;

if (commission < 39.00f)

commission = 39.00f;

// case of rival's commission

if (shares < 2000)

commission_rival = 33.00f + .03f * shares;

else

commission_rival = 33.00f + .02f * shares;

printf("Commission: %.2f\n", commission);

printf("Commission of rival: %.2f\n", commission_rival);

return 0;

}

4번 바람의 세기

#pragma warning(disable:4996)

#include <stdio.h>

int main()

{

int speed;

printf("Enter a wind speed(in knots, int form): ");

scanf("%d", &speed);

if (speed > 63)

printf("Hurricane");

else if (speed >= 48)

printf("Storm");

else if (speed >= 28)

printf("Gale");

else if (speed >= 4)

printf("Breeze");

else if (speed >= 1)

printf("Light air");

else

printf("Calm");

printf("\n");

return 0;

}

5번 소득세 문제

#pragma warning(disable:4996)

#include <stdio.h>

int main()

{

float income, tax;

printf("Enter the amount of taxable income: ");

scanf("%f", &income);

if (income <= 750)

tax = .01f * income;

else if (income <= 2250)

tax = 7.50f + .02f * (income - 750);

else if (income <= 3750)

tax = 37.50f + .03f * (income - 2250);

else if (income <= 5250)

tax = 82.50f + .04f * (income - 3750);

else if (income <= 7000)

tax = 142.50f + .05f * (income - 5250);

else

tax = 230.00f + .06f * (income - 7000);

printf("You have to pay $ %.2f for your income tax.\n", tax);

return 0;

}

6번 

#pragma warning(disable:4996)

#include <stdio.h>

int main()

{

int i1, i2, i3, i4, i5, i6, i7, i8, i9, i10, i11, i12, first_sum, second_sum, total, checkd;

printf("Enter the 12 digits of a UPC: ");

scanf("%1d%1d%1d%1d%1d%1d%1d%1d%1d%1d%1d%1d", &i1, &i2, &i3, &i4, &i5, &i6, &i7, &i8, &i9, &i10, &i11, &i12);

first_sum = i1 + i3 + i5 + i7 + i9 + i11;

second_sum = i2 + i4 + i6 + i8 + i10;

total = first_sum * 3 + second_sum;

checkd = (10 - total % 10) % 10;

if (i12 == checkd)

printf("VALID");

else

printf("NOT VALID");

return 0;

}

7번 4개의 정수를 입력받아 최대값과 최소값을 출력(if문 4개 이내로 쓰기)

#pragma warning(disable:4996)

#include <stdio.h>

int main()

{

int i1, i2, i3, i4, temp;

int smallest, largest;

printf("Enter four integers: ");

scanf("%d %d %d %d", &i1, &i2, &i3, &i4);

if (i1 > i2)  // 1개

{

temp = i2;

i2 = i1;

i1 = temp;

}

if (i3 > i4)  // 2개

{

temp = i4;

i4 = i3;

i3 = temp;

}

smallest = (i1 < i3) ? i1 : i3;  // 3개

largest = (i2 > i4) ? i2 : i4;  // 4개

printf("Largest : %d\n", largest);

printf("Smallest: %d\n", smallest);

}

9번 둘 중 어느 날짜가 빠른가?

#pragma warning(disable:4996)

#include <stdio.h>

int main()

{

int m1, d1, y1, m2, d2, y2;

int compare; // -1: first date is earlier, 0: two dates are same, 1: second date is earlier

printf("연도 2자리 앞에 생략된 수는 20으로 간주함\n");

printf("Enter first date (mm/dd/yy): ");

scanf("%d/%d/%d", &m1, &d1, &y1);

printf("Enter second date (mm/dd/yy): ");

scanf("%d/%d/%d", &m2, &d2, &y2);

if (y1 < y2)

compare = -1;

else if (y1 == y2)

{

if (m1 < m2)

compare = -1;

else if (m1 == m2)

{

if (d1 < d2)

compare = -1;

else if (d1 == d2)

compare = 0;

else

compare = 1;

}

else compare = 1;

}

else

compare = 1;

switch (compare)

{

case -1:

printf("%d/%d/%.2d is earlier than %d/%d/%.2d\n", m1, d1, y1, m2, d2, y2);

break;

case 0:

printf("%d/%d/%.2d is same as %d/%d/%.2d\n", m1, d1, y1, m2, d2, y2);

break;

case 1:

printf("%d/%d/%.2d is earlier than %d/%d/%.2d\n", m2, d2, y2, m1, d1, y1);

break;

}

return 0;

}

10번 100점 만점의 점수로 학점 매기기

#pragma warning(disable:4996)

#include <stdio.h>

int main()

{

int grade;

char letter_grade;

printf("Enter numerical grade: ");

scanf("%d", &grade);

if (grade < 0 || grade > 100)

{

printf("Invalid input.\n");

return 0;

}

switch (grade / 10)

{

case 10: case 9:         letter_grade = 'A'; break;

case 8: letter_grade = 'B'; break;

case 7: letter_grade = 'C'; break;

case 6: letter_grade = 'D'; break;

default:          letter_grade = 'F'; break;

}

printf("Letter grade: %c\n", letter_grade);

return 0;

}

11번 숫자를 영어로 읽으면?

#pragma warning(disable:4996)

#include <stdio.h>

int main()

{

int num;

printf("Enter a two-digit number: ");

scanf("%d", &num);

if (num < 9 || num > 99)

{

printf("Invalid input\n");

return 0;

}

printf("You entered the number ");

if (num >= 10 && num < 20)

{

switch (num)

{

case 11: printf("eleven"); break;

case 12: printf("twelve"); break;

case 13: printf("thirteen"); break;

case 14: printf("fourteen"); break;

case 15: printf("fifteen"); break;

case 16: printf("sixteen"); break;

case 17: printf("seventeen"); break;

case 18: printf("eighteen"); break;

case 19: printf("nineteen"); break;

return 0;

}

printf(".\n");

}

else

{

switch (num / 10)

{

case 2: printf("twenty"); break;

case 3: printf("thirty"); break;

case 4: printf("forty"); break;

case 5: printf("fifty"); break;

case 7: printf("sixty"); break;

case 8: printf("eighty"); break;

case 9: printf("ninety"); break;

}

switch (num % 10)

{

case 1: printf("-one"); break;

case 2: printf("-two"); break;

case 3: printf("-three"); break;

case 4: printf("-four"); break;

case 5: printf("-five"); break;

case 6: printf("-six"); break;

case 7: printf("-seven"); break;

case 8: printf("-eight"); break;

case 9: printf("-nine"); break;

}

printf(".\n"); 

return 0;

}

}

exercise 2번

i과 j가 양의 정수일 때, (-i)/j와 -(i/j)의 값이 항상 같은가?

C89에서는 그렇지 않다. i =5, j=2일 때 전자의 결과는 -3이 될 수도, -2가 될 수도 있다.

그러나 C99에서는 정수끼리의 나눗셈은 0에 가까운 쪽으로 내림(양수의 경우) 또는 올림(음수의 경우)하기 때문에, 두 값이 같아진다.

13번

i++와 ++i 중에 (i += 1)과 동일한 표현은 ++i이다. (i += 1) , ++i는 모두 i의 값이 더해지고 난 뒤에, expression의 값이 i가 된다.

Projects

3번 3자리 숫자를 입력 받아서 순서를 뒤집어서 출력

#pragma warning(disable:4996)

#include <stdio.h>

int main()

{

int i1, i2, i3;

printf("Enter a three-digit number: ");

scanf("%1d%1d%1d", &i1, &i2, &i3);

printf("The reversal is: %d%d%d\n", i3, i2, i1);

return 0;

}

4번 0부터 32767 사이의 정수를 입력받아 8진수로 출력하기(printf에서 제공하는 기능을 쓰지 않고 정수의 나눗셈을 이용)

#pragma warning(disable:4996)

#include <stdio.h>

int main()

{

int i, o1, o2, o3, o4, o5;

printf("Enter a number between 0 and 32767: ");

scanf("%5d", &i);

o5 = i % 8;

i /= 8;

o4 = i % 8;

i /= 8;

o3 = i % 8;

i /= 8;

o2 = i % 8;

o1 = i / 8;

printf("In octal, your number is: %d%d%d%d%d\n", o1, o2, o3, o4, o5);

return 0;

}

5번 

#pragma warning(disable:4996)

#include <stdio.h>

int main()

{

int i1, i2, i3, i4, i5, i6, i7, i8, i9, i10, i11, first_sum, second_sum, total, checkd;

printf("Enter the first 11 digits of a UPC: ");

scanf("%1d%1d%1d%1d%1d%1d%1d%1d%1d%1d%1d", &i1, &i2, &i3, &i4, &i5, &i6, &i7, &i8, &i9, &i10, &i11);

first_sum = i1 + i3 + i5 + i7 + i9 + i11;

second_sum = i2 + i4 + i6 + i8 + i10;

total = first_sum * 3 + second_sum;

checkd = (10 - total % 10) % 10;

printf("Check digit: %d\n", checkd);

}

6번 유럽의 13자리 코드(EAN)

#pragma warning(disable:4996)

#include <stdio.h>

int main()

{

int i1, i2, i3, i4, i5, i6, i7, i8, i9, i10, i11, i12, first_sum, second_sum, total, checkd;

printf("Enter the first 12 digits of a EAN: ");

scanf("%1d%1d%1d%1d%1d%1d%1d%1d%1d%1d%1d%1d", &i1, &i2, &i3, &i4, &i5, &i6, &i7, &i8, &i9, &i10, &i11, &i12);

first_sum = i2 + i4 + i6 + i8 + i10 + i12;

second_sum = i1 + i3 + i5 + i7 + i9 + i11;

total = first_sum * 3 + second_sum;

checkd = (10 - total % 10) % 10;

printf("Check digit: %d\n", checkd);

}

확인문제

1.

printf("%6d, %4d\n", 86, 1040); // 86 앞에 공백 4개, 1040은 그대로 표시

printf("%12.5e\n", 30.253); // _3.02530e+01 (총 12글자)

printf("%.4f\n", 83.162);  // 83.1620

printf("%-6.2g\n", .0000009979); // 유효숫자가 2개, 최소로 표시되는 문자 6개(더 적으면 뒤에 공백으로 채우고 왼쪽 정렬)

-----연습문제-----

1번(날짜 입력받아서 출력)

#pragma warning(disable:4996)

#include <stdio.h>

int main(void)

{

int m, d, y;

printf("Enter a date (mm/dd/yyyy): ");

scanf("%d/%d/%d", &m, &d, &y);

printf("You entered the date %.4d%.2d%.2d\n", y, m, d);

}

{

int gs1, group, publisher, item, checkd;

printf("Enter ISBN: ");

scanf("%d-%d-%d-%d-%d", &gs1, &group, &publisher, &item, &checkd);

printf("GS1 prefix: %d \nGroup identifier: %d \nPublisher code: %d \nItem number: %d \nCheck digit: %d \n", gs1, group, publisher, item, checkd);

}

4번

#pragma warning(disable:4996)

#include <stdio.h>

int main(void)

{

int x, y, z;

printf("Enter phone number [(xxx) xxx-xxxx]: ");

scanf("(%d) %d-%d", &x, &y, &z);

printf("You entered %d.%d.%d\n", x, y, z);

}

----연습문제----

5번

3x^5 + 2x^4 - 5x^3 - x^2 + 7x - 6

를 표현할 때, C에는 지수 오퍼레이터가 없는 관계로 x^5를 나타내려면 x*x*x*x*x로 써야 한다. 

따라서: 3 * x*x*x*x*x + 2 * x*x*x*x - 5 * x*x*x - x*x + 7 * x - 6라고 써야 한다.

((((3 * x + 2)*x - 5)*x - 1)*x + 7)*x - 6) 이렇게 쓸 수도 있다. (Horner's Rule)

7번 - int / int는 python의 a//b와 같다.

#pragma warning(disable:4996)

#include <stdio.h>

int main(void)

{

int dollar;

int bill_1, bill_5, bill_10, bill_20;

int rest;

printf("Enter a dollar amount: ");

scanf("%d", &dollar);

bill_20 = dollar / 20;

rest = dollar - 20 * bill_20;

bill_10 = rest / 10;

rest = rest - 10 * bill_10;

bill_5 = rest / 5;

bill_1 = rest - 5 * bill_5;

printf("$20 bills: %d \n$10 bills: %d \n $5 bills: %d \n $1 bills: %d\n", bill_20, bill_10, bill_5, bill_1);

}

8번

#pragma warning(disable:4996)

#include <stdio.h>

int main(void)

{

float amount, ir, monthly;

float total1, total2, total3;

printf("Enter amount of loan: ");

scanf("%f", &amount);

printf("Enter interest rate: ");

scanf("%f", &ir);

printf("Enter monthly paymetn: ");

scanf("%f", &monthly);

total1 = amount * (1 + ir / 1200) - monthly;

total2 = total1 * (1 + ir / 1200) - monthly;

total3 = total2 * (1 + ir / 1200) - monthly;

printf("Balance remaining after first payment: %.2f\n", total1);

printf("Balance remaining second first payment : %.2f\n", total2);

printf("Balance remaining third first payment : %.2f\n", total3);

}