一位網友正在學校做課程設計題目,要求在一個文件中找到給定單詞出現的位置並統計出現次數。這是一個比較簡單的文本處理問題， 於是， 我給他用 python 寫了一個，並打賭在5分鐘內用不到30行程序解決問題。
下面是程序：
if __name__=='__main__':
file_name = raw_input('Input the file you want to find in:')
try:
in_file = open(file_name,'r')
lines = in_file.readlines()
tag_tok = ''
while tag_tok.upper() != 'Q':
tag_tok = raw_input('Input the Word you want to find(Q for quit):')
if tag_tok.upper() != 'Q':
count = 0
line_no = 0
for line in lines:
line_no = line_no + 1
inline_cnt = line.count(tag_tok)
count = count + inline_cnt
if inline_cnt > 0:
print 'Find %s %d time(s) in line :%d'%(tag_tok,inline_cnt,line_no)
print line
print '---------------------------------'
print 'Total fount %s %d time(s)'%(tag_tok, count)
except:
print "Can't open file %s"%(file_name)
但是，這個網友還不滿足非要一個 C++的程序，理由是他們老師不會python ， 正好我也想試試用C++解決和python做下對比：
#include <fstream>
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
using namespace std;
int BruteFind(const char *x, int m, const char *y, int n ,vector<int>& colpos) {
int i, j, cnt=0;
/* Searching */
for (j = 0; j <= n - m; ++j) {
for (i = 0; i < m && x == y[i + j]; ++i);
if (i >= m){
colpos[cnt++] = j;
if(cnt == colpos.size())
colpos.resize(cnt * 2);
}
}
return cnt;
}
int count_string(string source, string tag, vector<int>& colpos){
int find_cnt = 0;
find_cnt = BruteFind(tag.c_str(), tag.size(), source.c_str(),source.size(),colpos);
return find_cnt;
}
int main(){
string file_name, line;
vector<string> lines;
lines.resize(10);
cout << "Input the file name:";
cin >> file_name;
ifstream in_file;
try{
in_file.open(file_name.c_str());
if(!in_file)
throw(file_name);
}
catch(string file_name){
cout << "Fatal error: File not found."<<endl;
exit(1);
}
int line_count = 0;
do{
getline(in_file, lines[line_count]);
line_count ++;
if(line_count == lines.size()){
lines.resize(line_count * 2);
}
}while(in_file.eof()==0);
string tag_tok;
vector<int> colpos;
colpos.resize(10);
do{
cout << "Input the word you want to find(Q for quit):";
cin >> tag_tok;
if(tag_tok == "Q"){
break;
}
int count = 0, line_no = 0 , inline_count;
for(line_no = 0 ;line_no < line_count ; line_no++){
inline_count = count_string(lines[line_no], tag_tok, colpos);
count += inline_count;
if(inline_count > 0){
cout << "Find " << tag_tok << " " << inline_count << " time(s) in line " << line_no ;
cout << " , column pos is ( ";
for(int i = 0 ;i< inline_count ;i++){
cout << colpos << ' ';
}
cout << " )" << endl;
cout << lines[line_no] << endl;
}
}
cout << "--------------------------------" <<endl;
cout << "Total fount " << tag_tok << " " << count << " time(s)" << endl;
}while(tag_tok != "Q");
in_file.close();
return 0;
}
這個程序用了30分鐘。
從程序長度和編程時間上，粗略對比下：
Python 5 分鐘 22行
C++ 30 分鐘 60多行
從這個簡單的例子中可以大體看到 腳本語言與C++語言中在開發時的差異了。
