C语言字符串练习：输入两个字符串并把他们链接起来 （不能用strcat函数）

/* C program to concatenate two strings without
 * using standard library function strcat()
 */
#include <stdio.h>
int main()
{
   char str1[50], str2[50], i, j;
   printf("\nEnter first string: ");
   scanf("%s",str1);
   printf("\nEnter second string: ");
   scanf("%s",str2);
   /* This loop is to store the length of str1 in i
    * It just counts the number of characters in str1
    * You can also use strlen instead of this.
    */
   for(i=0; str1[i]!='\0'; ++i); 
 
   /* This loop would concatenate the string str2 at
    * the end of str1
    */
   for(j=0; str2[j]!='\0'; ++j, ++i)
   {
      str1[i]=str2[j];
   }
   // \0 represents end of string
   str1[i]='\0';
   printf("\nOutput: %s",str1);
   
   return 0;
}

results: