CODEWITHSUNDEEP
c++
Hitan Elo
Hitan Elo

Reputation: 73

error: expected primary-expression before string

I would like to read a file and put the number of times the word appears in a std::map. So I made the following code:

#include <fstream>
#include <string>
#include <map>

    int main() {
    std::map<std::string, unsigned> M;
    std::ifstream declaration("declaration.txt");
    while(declaration >> std::string s){
        M[s]=0;
    }
    while(declaration >> std::string s){
        M[s]=M[s]+1;
    }
    declaration.close();
    return 0;
}

And I'm getting the following error messages:

text_analyse.cpp: In function ‘int main()’:
text_analyse.cpp:8:35: error: expected primary-expression before ‘s’
  while(declaration >> std::string s){
                                   ^
text_analyse.cpp:8:34: error: expected ‘)’ before ‘s’
  while(declaration >> std::string s){
       ~                          ^~
                                  )
text_analyse.cpp:8:35: error: ‘s’ was not declared in this scope
  while(declaration >> std::string s){
                                   ^
text_analyse.cpp:11:35: error: expected primary-expression before ‘s’
  while(declaration >> std::string s){
                                   ^
text_analyse.cpp:11:34: error: expected ‘)’ before ‘s’
  while(declaration >> std::string s){
       ~                          ^~
                                  )
text_analyse.cpp:11:35: error: ‘s’ was not declared in this scope
  while(declaration >> std::string s){
                                   ^

Upvotes: 0

Views: 644

Answers (1)

Botje
Botje

Reputation: 31183

std::string s is not a valid expression, it is a statement. Declare the string outside the loop instead:

std::string s;
while(declaration >> s){
    M[s]=0;
}

Upvotes: 1

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