delete matching characters from string

Question

Hi everyone,

Would someone be able to explain to me why the "if statement" and "s1[k] = '\0';" is necessary in the code. It works fine with just the two for loops. But i dont understand the reason for the if statement and setting "s1[k] to '\0', when i can just add a print statement to the second loop: printf("%c\n", s1[i];

The program below skips over chars from string1 that match any chars from string string2.
Appreciate any help.
Thank you.

void squeeze(char s1[], char s2[])
{
int i, j, k;

int len1 = strlen(s1);
int len2 = strlen(s2);

for (i = k = 0; i < len1; i++) {
for (j = 0; (s1[i] != s2[j]) && j < len2; j++)
;
if (s2[j] == '\0')
{
s1[k++] = s1[i];
}

}
s1[k] = '\0';
}

Answer 1

You can place your printf s1 after "s1[k] = '\0'", because this code find the different character and replace it to the begin of array, so k is the total of different char and '\0' is information of end of array, for example :
A = gerrad
B = david
The result of A will be "gerr" only

Answer 2

Tegar thank you for answering. I get it now.