1. 程式人生 > >【嵌入式系統學習記錄】練習:判斷一個字串是不是另一個字串的子串;(比如"ab"是"aabcd"的子串)

【嵌入式系統學習記錄】練習:判斷一個字串是不是另一個字串的子串;(比如"ab"是"aabcd"的子串)

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

char *jungle(char *p1, char *p2, int size1, int size2)
{
	int i, n, m;
	char *s1 = "NO!";
	char *s2 = "YES!";
/*	char *temp = (char *)malloc(sizeof(char) * 50);
	char *temp2 = temp;
	if(NULL == temp)
	{
		printf("malloc failure!\n");
		exit(1);
	}*/

	if(size1 <= size2)
	{
		return s1;
	}
	else
	{
		for(n = 0; n < size1 - size2 + 1; ++n)
		{
		/*	for(i = 0; i < size2; ++i)
			{
				*temp++ = *p1++;
			}
				temp = temp2;
			if(strcmp(temp, p2) != 0)
			{	
				temp++;
				for(m = 0; m < size2; ++m)
				{
					p1--;
				}
					p1++;
					*temp = *temp2;
					p1 = p1 -size2 + 1;
			}
			else
			{
				return s2;
				break;
			}*/
			if(strncmp(p2, p1+n, size2) == 0)//strncmp可以實現一定個數的字串相比較,省去了註釋掉的程式碼,減少了很多程式碼量
			{
				return s2;
			}
		}
		return s1;
	}

}


int main()
{
	int length1, length2;
	char *father = (char*)malloc(sizeof(char) * 50);
	char *son = (char*)malloc(sizeof(char) * 50);
	printf("please enter a long words:\n");
	scanf("%s",father);
	printf("please enter a short words:\n");
	scanf("%s",son);
	if(NULL == father || NULL == son)
	{
		printf("malloc failure!\n");
		exit(1);
	}
	length1 = strlen(father);
	length2 = strlen(son);
	printf("%s",jungle(father, son, length1, length2));//通過指標傳參和返回結果
	free(father);//malloc之後要通過手動釋放記憶體
	free(son);
	return 0;
}