#include <stdio.h>
#include <stdlib.h>
#include <iostream>
using namespace std;

// 函数StrCpy:复制字符串
// 参数：src-被复制的字符串
// 返回值：复制完的字符串
char* StrCpy(char* src)
{
	//计算长度
	int len = 0;
	while (src[len] != 0)
		len++;

	//申请内存
	char* dst = (char*)malloc(sizeof(char)*(len + 1));

	//复制字符串
	for (int i = 0; i < len; i++)
		dst[i] = src[i];
	dst[len] = '\0';

	return dst;
}


// 函数StrCat:连接字符串
// 参数：src1-被连接的字符串，src2-被连接的另外字符串
// 返回值：连接后的字符串
char* StrCat(char* str1, char* str2)
{
	int i = 0;
	int j = 0;

	//计算长度
	char* p= (char*)malloc(sizeof(char)*(10000));
	p = str1;
	while (*p != 0)
	{
		i++;
		p++;
	}
	p = str2;
	while (*p != 0)
	{
		j++;
		p++;
	}

	//申请内存
	char* L = (char*)malloc(sizeof(char)*(i + j + 2));

	//复制字符串
	for (int i1 = 0; i1 < i; i1++)
		L[i1] = str1[i1];
	for (int i2 = i; i2 < i + j; i2++)
		L[i2] = str2[i2 - i];
	L[i + j] = '\0';

	return L;
}


int main()
{
	//1.字符串的连接
		//创建内存空间 
	char* src1 = (char*)malloc(sizeof(char)*(100000));
	char* src2 = (char*)malloc(sizeof(char)*(100000));

	// 输入字符串
	std::cin >> src1;
	std::cin >> src2;
	char* L1 = StrCat(src1, src2);

	// 输出连接后的字符串
	cout << L1 << endl;

	//2.字符串的复制
		//创建内存空间
	char* src = (char*)malloc(sizeof(char)*(100000));

	// 输入字符串
	std::cin >> src;
	char* dst = StrCpy(src);

	// 输出复制后的字符串
	cout << dst << endl;

	if (L1 != NULL)
		delete L1;
	system("pause");
	return 0;
}