0519 - ccyomni/ex250310_second GitHub Wiki

#include <stdio.h>
int main()
{
	char* p = "ABC";
	//char p[4] = "ABC";
	//char p[4] = { 'A', 'B', 'C', '\0' };
	//char p[4] = { 'A', 'B', 'C' };

	printf("string : %s\n", p);
	printf("string : %s\n", &p[0]);
	//"ABC"
	printf("%c\n", p[0]);
	printf("%c\n", p[1]);
	printf("%c\n", p[2]);
	//'A' 'B' 'C'
}

#include <stdio.h>
int main()
{
	char* s1 = "ABC";
	char s2[] = "ABC"; //s2[] = s2[4], 4는 생략 가능

	printf("%s %s %s\n", s1, s2, "ABC");
}

#include <stdio.h>
int main()
{
	// 메모리, 변수, 상수
	int n = 10;
	int* pn = &n;

	printf("%d %d\n", n, *pn);
}

#include <stdio.h>
void PrintInteger(int data)
{
	printf("data : %d\n", data);
}
int main()
{
	int n = 10;
	
	PrintInteger(n);
	PrintInteger(n);
	PrintInteger(n);
}

#include <stdio.h>
void a()
{
	int n1 = 10;
	printf("n1 : %d\n", n1);

}
void b()
{
	int n2 = 10;
	printf("n2 : %d\n", n2);
}
void c()
{
	int n3 = 10;
	printf("n3 : %d\n", n3);
}
int main()
{
	a();
	b();
	c();
}

#include <stdio.h>
int g = 10;
int* pg = &g;

int main()
{
	int n = 10;
	int* pn = &n;

	printf("local : %d %d\n", n, *pn);
	printf("global : %d %d\n", g, *pg);
}

#include <stdio.h> //printf
#include <stdlib.h> //malloc, free
int main()
{
	int* p = malloc(4); //heap에 4바이트를 생성하라는 뜻

	*p = 10;
	printf("data : %d\n", *p);

	//free(p);
}

#include <stdio.h> //printf
#include <stdlib.h> //malloc, free
int main()
{
	int* p = malloc(sizeof(int)*4);

	p[0] = 10;
	p[1] = 20;
	p[2] = 30;
	p[3] = 40;

	printf("data : %d\n", p[0]);
	printf("data : %d\n", p[1]);
	printf("data : %d\n", p[2]);
	printf("data : %d\n", p[3]);

	free(p);
}

#include <stdio.h> //printf
#include <stdlib.h> //malloc, free
int main()
{
	double d = 5.5;
	double* pk = NULL;
	pk = malloc(sizeof(double) * 2);

	pk[0] = 1.1;
	pk[1] = 2.2;
	for (int i = 0; i < 2; ++i)
		printf("double : %g\n", pk[i]);
	free(pk);
}

#include <stdio.h> //printf
#include <stdlib.h> //malloc, free
int main()
{
	double d = 5.5;
	double* pk = NULL;
	pk = malloc(sizeof(double) * 2);
	if (pk == NULL)
	{
		printf("pk NULL일 수 없다.");
		return -1;
	}

	pk[0] = 1.1;
	pk[1] = 2.2;
	for (int i = 0; i < 2; ++i)
		printf("double : %g\n", pk[i]);
	free(pk);
}

#include <stdio.h> //printf
#include <stdlib.h> //malloc, free
int main()
{
	double* pk = malloc(sizeof(double));
	
	*pk = 100.1;
	pk[0] = 299.2;

	free(pk);
}