_21_문제 => 문제027_포인터와함수05 ~ 문제027_포인터와함수14 (1~3)

• _21_문제

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• 문제027_포인터와함수05.cpp

#include <stdio.h>
#include <stdlib.h>

double h(double *f, int d, double x){
	int i;
	double res = 0.0;
	for(i = d-1; i >= 0; i--){ // 3 ; i >=0
		//3 2 1 0 
		res = res * x + f[i]; 
		// 0 * 2 + 4 // 4 
		// 4 * 2 + 3 // 11 
		// 11 * 2 + 2 // 24 
		// 24 * 2 + 1 // 49 
		printf("%3.1f \n" , res); //50 
	}
	return res;
}

int main(void) {
	double f[] = {1, 2, 3, 4};
	double res = h(f, 4, 2);
	printf("%3.1f \n" , res);
	return 0;
}


// 102번

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• 문제027_포인터와함수06.cpp

#include <stdio.h>
#include <stdlib.h>

void func(int *a, int b, int *c);

int main(void) {
	int a, b, c[1];
	a = 20;
	b = 20;
	c[0] = 20;

	func(&a, b, c);// &c[0]

	printf("%d %d %d\n" , a , b , c[0]); // 20 20 19 
	return 0;
}
			//x1 , 20   , x5 
void func(int *a, int b, int *c){
	int x;	
	x = *a; //x = 20 
	*a = x ++; //a = 20 , x = 21 
	x = b; 	//x = 20 
	b = ++x; //b = 21 ,x = 21 
	--(*c);//19 
}


// 102번

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• 문제027_포인터와함수07.cpp

#include <stdio.h>

#define SIZE 3

void func(int *m, int *a, int b);

int main(void) {

	int num[SIZE] = {1, 3, 6};

	int a = 10, b = 30;

	func(num, &a, b);

	printf("%d %d \n",a , b); // 7 30 

	return 0;
}
		 //x1, x 13 , 30 
void func(int *m, int *x, int y){

	int i = 0, n = 0;

	y = *x;	//y = 10 
	
	//n = 3 + 3 // n = 6
	n = *(m + 1) + (*m + 2);
	//a = 7 
	*x = ++n;
}

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• 문제027_포인터와함수08.cpp

#include <stdio.h>

#define SIZE 3

//10 , x1 
int* func(int a, int *x){
	a = a + 10; // a = 20 
	x = x + 1; // x5 
	*x = *x * 2;//*(x5) =>a[1] => 20 
	return x;
}

int main(void) {
	int i;
	int x = 10;
	int *p;
	int a[100];

	for (i = 0; i < 100; i++)
		a[i] = i * 10; // 0, 10, 20, ... 990 

	p = func(x, a); //x5 

	int sum = x + a[0] + a[1] + p[0] + p[1];
				//10 + 0 + 20 + 20 +20 =70
				//p[0] == a[1] , // p[1] == a[2]

	printf("%d\n" , sum);
		
	return 0;
}

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• 문제027_포인터와함수09.cpp

#include <stdio.h>

void funCount();


int main(void) {
	int num;

	//2번 동작 //0,1 => funCount()가 두번 동작 
	for(num = 0; num < 2; num++)
		funCount();
		
	return 0;
}

void funCount(){
	int num = 0;
	static int count;
	printf("%d %d\n" , ++num, count++); //1, 0 // 1 1 
}

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• 문제027_포인터와함수11.cpp

#include <stdio.h>

int funcA(int n){
	static int s = 1;
	s *= n;
	return s;
}

int funcB(int n){
	int s = 1;
	s *= n;
	return s;
}

int main(void) {
	int s1, s2;
	s1 = funcA(2);
	printf("%d\n" , s1); //2
	
	s1 = funcA(3);
	printf("%d\n" , s1); //6
	
	s2 = funcB(2);
	printf("%d\n" , s2); //2
	
	s2 = funcB(3);
	printf("%d\n" , s2); //3
	
	return 0;
}

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• 문제027_포인터와함수12.cpp

#include <stdio.h>
void func();

int a = 10;
int b = 20;
int c = 30;

int main(void) {
	func();
	func();
	printf("%d %d %d\n" , a , b , c);	//10 20 102 
	
	return 0;
}

void func(){
	static int a = 100;
	int b = 200;
	a ++;
	b ++;
	c = a;
}