exercises 2-4

#include <stdio.h>void squeeze(char s1[],char s2[]);int main(int argc, char *argv[]){    char s1[]="2819whatevfr";    char s2[]="238wvfr";    squeeze(s1,s2);    printf("after processed:\n%s\n",s1);    return 0;}void squeeze(char s1[],char s2[]){    enum boolean {NO,YES};    int i,j,k;    k=0;    for(i=0; s1[i]!='\0'; i++)    {        enum boolean found=NO;        for(j=0; s2[j]!='\0'; j++)        {            if(s1[i]==s2[j])            {                found=YES;            }        }        if(found==NO)        {            s1[k]=s1[i];            k++;        }    }    s1[k]='\0';}