Language: C++

//
// Created by ?????°?????? on 2016/06/21.
//

#include <iostream>
#include <string>
using namespace std;

void KMP(string T, string P){
    int t=T.size();
    int p=P.size();
    int i,j,k;

    vector<int> next(p);
    int nex;
    i=2;j=0 ;
    if(p == 1){
        next[0] = -1;
        nex = 0;
    }else{
        next[0]=-1;
        next[1]=0;
        while(i + p+1){
            if(i == p){
                nex = j+1;
            }else{
                next[i] = j+1;
            }
            i++;
            j++;
        }else if(j>0){
            j = next[j];
        }else{
            if(i == P){
                nex= 0;
            }else{
                next[i] = 0;
            }
            i ++;
        }
    }
    i = 0;
    j = 0;
    while(i<t){
        if (T[i+j] == P[j]){
            j++;
            if(j == p){
                cout << i << endl;
                i ++;
                j = nex;
            }
        }else{
            i = i + j -next[j];
            if(j>0) j = next[j];
        }
    }
}

int main(){
    string T,P;
    cin >> T >> P;
    KMP(T,P);
    return 0;
}

Compiler output:
a.cc: In function 'void KMP(std::string, std::string)':
a.cc:14:5: error: 'vector' was not declared in this scope
   14 |     vector<int> next(p);
      |     ^~~~~~
a.cc:6:1: note: 'std::vector' is defined in header '<vector>'; this is probably fixable by adding '#include <vector>'
    5 | #include <iostream>
  +++ |+#include <vector>
    6 | #include <string>
a.cc:14:12: error: expected primary-expression before 'int'
   14 |     vector<int> next(p);
      |            ^~~
a.cc:18:13: error: invalid types '<unresolved overloaded function type>[int]' for array subscript
   18 |         next[0] = -1;
      |             ^
a.cc:21:13: error: invalid types '<unresolved overloaded function type>[int]' for array subscript
   21 |         next[0]=-1;
      |             ^
a.cc:22:13: error: invalid types '<unresolved overloaded function type>[int]' for array subscript
   22 |         next[1]=0;
      |             ^
a.cc:27:21: error: invalid types '<unresolved overloaded function type>[int]' for array subscript
   27 |                 next[i] = j+1;
      |                     ^
a.cc:31:10: error: 'else' without a previous 'if'
   31 |         }else if(j>0){
      |          ^~~~
a.cc:32:21: error: invalid types '<unresolved overloaded function type>[int]' for array subscript
   32 |             j = next[j];
      |                     ^
a.cc:34:18: error: no match for 'operator==' (operand types are 'int' and 'std::string' {aka 'std::__cxx11::basic_string<char>'})
   34 |             if(i == P){
      |                ~ ^~ ~
      |                |    |
      |                int  std::string {aka std::__cxx11::basic_string<char>}
In file included from /usr/include/c++/14/iosfwd:42,
                 from /usr/include/c++/14/ios:40,
                 from /usr/include/c++/14/ostream:40,
                 from /usr/include/c++/14/iostream:41,
                 from a.cc:5:
/usr/include/c++/14/bits/postypes.h:192:5: note: candidate: 'template<class _StateT> bool std::operator==(const fpos<_StateT>&, const fpos<_StateT>&)'
  192 |     operator==(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs)
      |     ^~~~~~~~
/usr/include/c++/14/bits/postypes.h:192:5: note:   template argument deduction/substitution failed:
a.cc:34:21: note:   mismatched types 'const std::fpos<_StateT>' and 'int'
   34 |             if(i == P){
      |                     ^
In file included from /usr/include/c++/14/string:43,
                 from /usr/include/c++/14/bits/locale_classes.h:40,
                 from /usr/include/c++/14/bits/ios_base.h:41,
                 from /usr/include/c++/14/ios:44:
/usr/include/c++/14/bits/allocator.h:235:5: note: candidate: 'template<class _T1, class _T2> bool std::operator==(const allocator<_CharT>&, const allocator<_T2>&)'
  235 |     operator==(const allocator<_T1>&, const allocator<_T2>&)
      |     ^~~~~~~~
/usr/include/c++/14/bits/allocator.h:235:5: note:   template argument deduction/substitution failed:
a.cc:34:21: note:   mismatched types 'const std::allocator<_CharT>' and 'int'
   34 |             if(i == P){
      |                     ^
In file included from /usr/include/c++/14/string:48:
/usr/include/c++/14/bits/stl_iterator.h:441:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator==(const reverse_iterator<_Iterator>&, const reverse_iterator<_Iterator>&)'
  441 |     operator==(const reverse_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:441:5: note:   template argument deduction/substitution failed:
a.cc:34:21: note:   mismatched types 'const std::reverse_iterator<_Iterator>' and 'int'
   34 |             if(i == P){
      |                     ^
/usr/include/c++/14/bits/stl_iterator.h:486:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator==(const reverse_iterator<_Iterator>&, const reverse_iterator<_IteratorR>&)'
  486 |     operator==(const reverse_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:486:5: note:   template argument deduction/substitution failed:
a.cc:34:21: note:   mismatched types 'const std::reverse_iterator<_Iterator>' and 'int'
   34 |             if(i == P){
      |                     ^
/usr/include/c++/14/bits/stl_iterator.h:1667:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator==(const move_iterator<_IteratorL>&, const move_iterator<_IteratorR>&)'
 1667 |     operator==(const move_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1667:5: note:   template argument deduction/substitution failed:
a.cc:34:21: note:   mismatched types 'const std::move_iterator<_IteratorL>' and 'int'
   34 |             if(i == P){
      |                     ^
/usr/include/c++/14/bits/stl_iterator.h:1737:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator==(const move_iterator<_IteratorL>&, const move_iterator<_IteratorL>&)'
 1737 |     operator==(const move_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1737:5: note:   template argument deduction/substitution failed:
a.cc:34:21: note:   mismatched types 'const std::move_iterator<_IteratorL>' and 'int'
   34 |             if(i == P){
      |                     ^
In file included from /usr/include/c++/14/bits/stl_algobase.h:64,
                 from /usr/include/c++/14/string:51:
/usr/include/c++/14/bits/stl_pair.h:1033:5: note: candidate: 'template<class _T1, class _T2> constexpr bool std::operator==(const pair<_T1, _T2>&, const pair<_T1, _T2>&)'
 1033 |     operator==(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_pair.h:1033:5: note:   template argument deduction/substitution failed:
a.cc:34:21: note:   mismatched types 'const std::pair<_T1, _T2>' and 'int'
   34 |             if(i == P){
      |                     ^
In file included from /usr/include/c++/14/bits/basic_string.h:47,
                 from /usr/include/c++/14/string:54:
/usr/include/c++/14/string_view:629:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator==(basic_string_view<_CharT, _Traits>, __type_identity_t<basic_string_view<_CharT, _Traits> >)'
  629 |     operator==(basic_string_view<_CharT, _Traits> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:629:5: note:   template argument deduction/substitution failed:
a.cc:34:21: note:   mismatched types 'std::basic_string_view<_CharT, _Traits>' and 'int'
   34 |             if(i == P){
      |                     ^
/usr/include/c++/14/string_view:637:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator==(basic_string_view<_CharT, _Traits>, basic_string_view<_CharT, _Traits>)'
  637 |     operator==(basic_string_view<_CharT, _Traits> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:637:5: note:   template argument deduction/substitution failed:
a.cc:34:21: note:   mismatched types 'std::basic_string_view<_CharT, _Traits>' and 'int'
   34 |             if(i == P){
      |                     ^
/usr/include/c++/14/string_view:644:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator==(__type_identity_t<basic_string_view<_CharT, _Traits> >, basic_string_view<_CharT, _Traits>)'
  644 |     operator==(__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:644:5: note:   template argument deduction/substitution failed:
a.cc:34:21: note:   'std::__cxx11::basic_string<char>' is not derived from 'std::basic_string_view<_CharT, _Traits>'
   34 |             if(i == P){
      |                     ^
/usr/include/c++/14/bits/basic_string.h:3755:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> bool std::operator==(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3755 |     operator==(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3755:5: note:   template argument deduction/substitution failed:
a.cc:34:21: note:   mismatched types 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>' and 'int'
   34 |             if(i == P){
      |                     ^
/usr/include/c++/14/bits/basic_string.h:3772:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> bool std::operator==(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, const _CharT*)'
 3772 |     operator==(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3772:5: note:   template argument deduction/substitution failed:
a.cc:34:21: note:   mismatched types 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>' and 'int'
   34 |             if(i == P){
      |                     ^
/usr/include/c++/14/bits/basic_string.h:3819:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> bool std::operator==(const _CharT*, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3819 |     operator==(const _CharT* __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3819:5: note:   template argument deduction/substitution failed:
a.cc:34:21: note:   mismatched types 'const _CharT*' and 'int'
   34 |             if(i == P){
      |                     ^
In file included from /usr/include/c++/14/bits/memory_resource.h:47,
                 from /usr/include/c++/14/string:68:
/usr/include/c++/14/tuple:2558:5: note: candidate: 'template<class ... _TElements, class ... _UElements> constexpr bool std::operator==(const tuple<_UTypes ...>&, const tuple<_Elements ...>&)'
 2558 |     operator==(const tuple<_TElements...>& __t,
      |     ^~~~~~~~
/usr/include/c++/14/tuple:2558:5: note:   template argument deduction/substitution failed:
a.cc:34:21: note:   mismatched types 'const std::tuple<_UTypes ...>' and 'int'
   34 |             if(i == P){
      |                     ^
In file included from /usr/include/c++/14/bits/locale_facets.h:48,
                 from /usr/include/c++/14/bits/basic_ios.h:37,