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我寫一個程序,讀取和寫入.txt文件和C++一個字符的值。這裏是我的代碼部分編輯的樣本:您在C++中的字符串
#include <iostream>
#include <stdio.h>
#include <fstream>
#include <string>
#include <windows.h>
#include <sstream>
#include <algorithm>
//functions
template <typename T>
string num_to_string(T pNumber)
{
ostringstream oOStrStream;
oOStrStream << pNumber;
return oOStrStream.str();
}
bool isdot(const char &c)
{
return '.'==c;
}
//needed for string_to_num()
float string_to_num(string s)
{
s.erase(remove_if(s.begin(), s.end(), &isdot),s.end());
replace(s.begin(), s.end(), ',', '.');
stringstream ss(s);
float v = 0;
ss >> v;
return v;
}
//code
string line = 10/20;
//the line taken from the .txt file
float add_numerator = 5;
float add_denominator = 10;
//these are values just for example
for(int i = 0; i < line.size(); i+= 1) {
if (numerator_finished == false){
if (line[i] != "/"){
numerator += line[i];
}else {
numerator_finished = true;
}
}else {
denominator += line[i];
}
}
float numerator_temp = string_to_num(numerator);
float denominator_temp = string_to_num(denominator);
numerator_temp += add_numerator;
denominator_temp += add_denomitator;
numerator = num_to_string(numerator_temp);
denominator = num_to_string(denominator_temp);
string add_string = numerator + "/" + denominator;
//add_string is what the line in the .txt file is changed to with not shown code
如果此代碼運行時,它應該是add_string =「15/30」。然而,它不會因爲該行的編譯:
if (line[i] != "/"){
因爲該行出現此錯誤:
「ISO C++禁止指針和整數之間的比較[-fpermissive]」
我不明白怎麼當它們都是字符串時,這是一個指針和一個整數。
可以這樣錯誤地解釋並出示解決?
只需使用字符文字:'如果(行[I] = '/'!){'' –
「/」'是一個字符串,你正在努力尋找一個字符。你需要''/''。 – NathanOliver
傢伙。停止回答評論!!!! –