KMP MATCHER

#include<iostream>
#include<string>
void comp_prefix_func(int *p,std::string pat)
{
    int j=0;
    p[0]=0;
    for(int i=1;i<pat.length();++i)
    {
        while(j>0 && pat[j]!=pat[i])
            j=p[j-1];
        if(pat[j]==pat[i])
            j++;
        p[i]=j;
    }
}
void kmp(std::string text,std::string pat)
{
    int n=text.length(),m=pat.length(),j=0,c=0,*p=new int[m];
    comp_prefix_func(p,pat);
    for(int i=0;i<n;++i)
    {
        while(j>0 && pat[j]!=text[i])
            j=p[j-1];
        if(pat[j]==text[i])
            j++;
        if(j==m)
        {
            std::cout<<"Pattern occurs between "<<i-m+1<<" and "<<i<<"\n";
            j=p[j-1];
        }
    }
    delete []p;
}
int main()
{
    std::string s1,s2;
    std::cout<<"Enter two strings: \n";
    std::getline(std::cin,s1);
    std::getline(std::cin,s2);
    kmp(s1,s2);
}