C program that appends the one string to another string

/* C program that appends the one string to another string. */

#include"stdio.h"

#include"string.h"

void main()

{

char str1[100], str2[20];

int i, j, k, slen;

printf("Enter first string: \n");

scanf("%s", str1);

printf("Enter another string: \n");

scanf("%s", str2);

slen = strlen(str1);

for(i=0, j=slen; str2[i] != '\0', str1[j] != str2[i]; i++, j++)

{

str1[j] = str2[i];

}

printf("%s", str1);

printf("\n");

}

Output: