토크나이저 - 문제해결기법 튜터링

#include "stdafx.h" #include <iostream> using namespace std; const int MAX_LEN = 1024; const int MAX_TOKEN = 100; const int TOKEN_NUMBER=1; const int TOKEN_FUNCTION=2; const int TOKEN_PARETHESIS=3; const int TOKEN_OPERATOR=4; void preprocess_input(char *input); bool check_exit(char *input); int get_token_positions(char *input, int position[][2]); void print_tokens(int token_count, int position[][2], char *input); void triming_input(char *input); void make_lower(char *input); void tokenizing(char *input, char *delim, int position[][2], int &count); void sort_position(int count, int position[][2]); void find_parenthesis(char *input, int position[][2], int &count); int token_values(int count, char *input, int position[][2], int *type, double *value); int check_tokens(int count, int *type, double *value); int evaluate_sentence( int count, int *type, double *value, double &result); void get_token_string(int start, int end, char *input, char *token); bool is_numbers(char *token); bool is_parenthesis(char *token); bool is_operator(char *token); void print_sentence(int count, int *type, double *value); void main(int argc, char* argv[]) { char input[MAX_LEN]; int token_count; int position[MAX_TOKEN][2]; bool break_condition = false; int error_code; int type[MAX_TOKEN]; double value[MAX_TOKEN], result; do{ cout << ">> "; // 한 라인을 입력 cin.getline(input, MAX_LEN); preprocess_input(input); // 입력 라인에 대한 전처리 // cout << "|" << input << "|" << endl; if(check_exit(input)) break; // 종료 조건 검사 token_count = get_token_positions(input, position); // 토큰 위치 계산 print_tokens(token_count, position, input); // 토큰 출력 //토큰을 값으로 변환한다. error_code=token_values(token_count, input, position, type, value); if(error_code){ cout<<"*수식에 오류가 있습니다.\n"; continue; } print_sentence(token_count,type,value); //토큰의 오류를 검사한다. error_code= check_tokens(token_count, type, value); //수식을 계산한다. error_code= evaluate_sentence(token_count, type, value, result); cout<<"="<<result<<endl; }while(!break_condition); } void preprocess_input(char *input) { // 시작과 끝 부분의 공백 제거 triming_input(input); // 소문자로 알파벳 문자를 통일 make_lower(input); } void triming_input(char *input) { int len = strlen(input), start = 0, end = len - 1; while(input[start] == ' ' || input[start] == '\t'){ start++; } while(input[end] == ' ' || input[end] == '\t'){ end--; } if(end >= start){ for(int i = start; i <= end; i++) input[i - start] = input[i]; input[end - start + 1] = '\0'; } else input[0] = '\0'; } void make_lower(char *input) { int len = strlen(input); for(int i = 0; i < len; i++){ if(input[i] >= 'A' && input[i] <= 'Z') input[i] = input[i] + 'a' - 'A'; } } bool check_exit(char *input) { // strcmp : return 0 when match if(!strcmp(input, "exit")) return true; if(!strcmp(input, "quit")) return true; return false; } void print_tokens(int token_count, int position[][2], char *input) { for(int i = 0; i < token_count; i++){ cout.width(4); cout << position[i][0]; cout.width(4); cout << position[i][1] << " : "; for(int j = position[i][0]; j <= position[i][1]; j++) cout << input[j]; cout << endl; } } void tokenizing(char *input, char *delim, int position[][2], int &count) { char *pch; pch = strtok(input, delim); while(pch != NULL){ int start, end; start = pch - input; end = start + strlen(pch) - 1; position[count][0] = start; position[count][1] = end; count++; pch = strtok(NULL, delim); } } void sort_position(int count, int position[][2]) { int temp; for(int i = 0; i < count - 1; i++){ for(int j = i + 1; j < count; j++){ if(position[i][0] > position[j][0]){ temp = position[i][0]; position[i][0] = position[j][0]; position[j][0] = temp; temp = position[i][1]; position[i][1] = position[j][1]; position[j][1] = temp; } } } } void find_parenthesis(char *input, int position[][2], int &count) { int len = strlen(input); for(int i = 0; i < len; i++){ if(input[i] == '(' || input[i] == ')'){ position[count][0] = i; position[count][1] = i; count++; input[i] = ' '; } } } int get_token_positions(char *_input, int position[][2]) { char input[MAX_LEN], input1[MAX_LEN]; char delim1[] = " \t+-*/()"; char delim2[] = " \t1234567890."; strcpy(input, _input); int count = 0; // number of tokens // 괄호를 찾고 지운다. find_parenthesis(input, position, count); // 연산자도 괄호를 찾는 것과 유사한 방식으로 찾고 지움으로써 // 이후 처리를 간단히 할 수 있다. // tokenizing strcpy(input1, input); tokenizing(input1, delim1, position, count); // numbers strcpy(input1, input); tokenizing(input1, delim2, position, count); // operators // sort sort_position(count, position); return count; } int token_values(int count, char *input, int position[][2], int *type, double *value) { char token[100]; for(int i=0; i<count; i++) { get_token_string(position[i][0], position[i][1], input, token); if(is_numbers(token)){ type[i]=TOKEN_NUMBER; value[i]=atof(token); } else if(is_parenthesis(token)){ type[i]=TOKEN_PARETHESIS; if(token[0]=='(')value[i]=-1; else value[i]=1; } else if(is_operator(token)){ type[i]=TOKEN_OPERATOR; value[i]=token[0]; } else { return 1; //no error } } return 0;//no error } int check_tokens(int count, int *type, double *value) { return 0; //no error } int evaluate_sentence( int count, int *type, double *value, double &result) { result=1; return 0; //no error } void get_token_string(int start, int end, char *input, char *token) { int pos=0; for(int j=start; j<=end; j++) { token[pos]=input[j]; pos++; } token[pos]='\0'; } bool is_numbers(char *token) { int len=strlen(token); for(int i=0; i<len ; i++) { if(token[i]>='0' && token[i]<='9') continue; else if(token[i]=='.')continue; else return false; } return true; } bool is_parenthesis(char *token) { if(token[0]=='(' || token[0]==')')return true; return false; } bool is_operator(char *token) { if(token[0]=='+' || token[0]=='-' || token[0]=='*' || token[0]=='/')return true; return false; } void print_sentence(int count, int *type, double *value) { for(int i=0; i<count ; i++) { switch(type[i]){ case TOKEN_NUMBER: cout<<" "<<value[i]; break; case TOKEN_PARETHESIS: if(value[i]==-1)cout<<" ("; else cout<<")"; break; case TOKEN_OPERATOR: cout<<" "<<(char)value[i]; break; } } cout<<endl; }