새싹교실/2020/새싹부터나무까지/박소은/실습/20.10.09: Difference between revisions

Latest revision as of 01:08, 27 March 2026

1

//strcpy

char* strcpy(char s1[], char s2[])
{
	int i = 0;
	while (*(s2 + i))
	{
		s1[i] = s2[i];
		i++;
	}
	s1[i] = s2[i];
	return s1;
}

2

//strlen

int strlen(char* p)
{
	int length = 0, i = 0;
	while (*(p + i)) {
		length++;
		i++;
	}
	return length;
}

3

//strcat

void strcat(char s1[], char s2[])
{
	for (int i = strlen(s1), j = 0; i <= strlen(s1) + strlen(s2); i++, j++)
	{
		s1[i] = s2[j];
	}
}

4

//strcmp

int strcmp(char s1[], char s2[])
{
	int i = 0;
	while (s1[i] != '\0' || s2[i] != '\0')
	{
		if (s1[i] > s2[i])
			return 1;
		else if (s1[i] < s2[i])
			return -1;
		i++;
	}
	return 0;
}

@@ Line 1: / Line 1: @@
 == 1 ==
- #include &lt;stdio.h&gt;
+  //strcpy
-  //*를 사용하되, 포인터(p)를 사용하지 마시오.
-  int main(void)
+  char* strcpy(char s1&#91;&#93;, char s2&#91;&#93;)
   {
-  	int number[10] = { 1,3,5,7,9,11,13,15,17,19 };
+  	int i = 0;
-  	int i, * p;
+  	while (*(s2 + i))
- 	for (i = 0; i &lt; 10; i++)
   	{
-  		printf("%d\n", *(number + i));
+  		s1&#91;i&#93; = s2&#91;i&#93;;
+ 		i++;
   	}
+ 	s1&#91;i&#93; = s2&#91;i&#93;;
-  	return 0;
+  	return s1;
   }
 == 2 ==
   //strlen
-  int strlen(const char* p)
+  int strlen(char* p)
   {
   	int length = 0, i = 0;
@@ Line 30: / Line 28: @@
   //strcat
-  void strcat(char s1[], const char s2[])
+  void strcat(char s1&#91;&#93;, char s2&#91;&#93;)
   {
-  	for (int i = strlen(s1); i &lt; strlen(s1) + strlen(s2); i++)
+  	for (int i = strlen(s1), j = 0; i &lt;= strlen(s1) + strlen(s2); i++, j++)
   	{
-  		s1[i] = s2[i];
+  		s1&#91;i&#93; = s2&#91;j&#93;;
   	}
   }
 == 4 ==
- #include &lt;stdio.h&gt;
+  //strcmp
-  //포인터를 사용하지 마시오.
-  int main(void)
+  int strcmp(char s1&#91;&#93;, char s2&#91;&#93;)
   {
-  	int number[3][4] = { {1,3,5,7},{9,11,13,15},{17,19,21,23} };
+  	int i = 0;
-  	int i, j, * p;
+  	while (s1&#91;i&#93; != '\0' || s2&#91;i&#93; != '\0')
- 	for (i = 0; i &lt; 3; i++)
   	{
-  		for (j = 0; j &lt; 4; j++)
+  		if (s1&#91;i&#93; &gt; s2&#91;i&#93;)
-  		{
+ 			return 1;
- 			printf("%d\n", *(*(number + i) + j));
+  		else if (s1&#91;i&#93; &lt; s2&#91;i&#93;)
-  		}
+ 			return -1;
+  		i++;
   	}
   	return 0;
   }