쉽게 풀어쓴 C언어 EXPRESS(개정 3판) - Chapter 9-2

5.

#include <stdio.h>

#include <stdlib.h>

void save();

void draw();

int balance;

int main(void) {

int menu;

while (1) {

printf("메뉴를 선택하세오: 저축(1), 인출(2): ");

scanf("%d", &menu);

if (menu == 1)

save(); 

else if (menu == 2)

draw(); 

else

break;

printf("현재 잔액은 %d입니다.\n", balance);

}

return 0;

}

void save() {

int amount;

printf("저축할 금액: ");

scanf("%d", &amount);

balance += amount;

}

void draw() {

int amount;

printf("인출할 금액: ");

scanf("%d", &amount);

balance -= amount;

}

6.

#include <stdio.h>

int get_tri_number(int n) {

if (n == 1) 

return 1; 

else 

return n + get_tri_number(n - 1);

}

int main(void) {

printf("%d\n", get_tri_number(4));

return 0;

}

7.

#include <stdio.h>

int recursive(int n, int k) {

if (n == 1 || n == k) 

return 1; 

else 

return recursive(n - 1, k - 1) + recursive(n - 1, k);

}

int main(void) {

printf("%d\n", recursive(3, 2));

return 0;

}

8.

#include <stdio.h>

int show_digit(int x) {

if (x / 10 > 0)

show_digit(x / 10);

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

}

int main(void) {

int n;

printf("정수를 입력하시오: ");

scanf("%d", &n);

show_digit(n);

return 0;

}