string类型的"0.9144"如何转换成float类型的0.9144?

[zhzh1126]

string类型的"0.9144"如何转换成float类型的0.9144?

[super_admi]

用函数atof?

[水平不流]

atof函数可以实现.

[zhctj159]

atof <math.h> and <stdlib.h> double atof( const char *string );

[net_assassin]

lz是不是在做渣打银行codemarathon的那个测试题啊 呵呵 atof

[net_assassin]

我写的代码：望指教

#include <iostream>
#include <iomanip>
#include <string>
#include <fstream>
#include <sstream>
#include <map>

using namespace std;

ifstream input("input.txt");
ofstream output("output.txt");

map<string,string> divisionMap;

double deal(string str1,string str2)
{
	if (str2 == "feet")
	{
		str2 = "foot";
	}
	map<string,string>::iterator it = divisionMap.find(str2);
	if (it == divisionMap.end())
	{
		it = divisionMap.find(str2.substr(0,str2.length()-1));
		if (it == divisionMap.end())
		{
			it = divisionMap.find(str2.substr(0,str2.length()-2));
			if (it == divisionMap.end())
			{
				return 0;
			}
		}
	}
	
	return atof(str1.c_str())*atof((it->second).c_str());
}

int main()
{
	double sum = 0.0;
	string strline = " ";
	string strword1 = " ";
	string strword2 = " ";
	string division,meters;

	while (getline(input,strline) && strline != "")//建立 转换关系映射
	{
		istringstream line(strline);
		while(line>>division>>division>>meters>>meters)
		{
			divisionMap.insert(make_pair(division,meters));
		}
	}

	output<<"[e-mail]"<<endl<<endl;
	bool minus = false;
	while(getline(input,strline) && strline != " ") //处理表达式
	{
		istringstream line(strline);
		while(line>>strword1)
		{
			if (strword1 == "+")
			{
				continue;
			}
			if (strword1 == "-")
			{
				minus = true;
				continue;
			}
			line>>strword2;
			
			if (minus)
			{
				sum += -deal(strword1,strword2);
				minus = false;
			}else{
				sum += deal(strword1,strword2);
			}
		}
	    output<<setiosflags(ios::fixed)<<setprecision(2)<<sum<<" m"<<endl;
		sum = 0;
	}
	input.close();
	output.close();
	return 0;
}

[qq120848369]

NAME strtod, strtof, strtold - convert ASCII string to floating-point number SYNOPSIS #include <stdlib.h> double strtod(const char *nptr, char **endptr); float strtof(const char *nptr, char **endptr); long double strtold(const char *nptr, char **endptr);

[jiandingzhe]

你可以用C++标准库的istringstream，boost的lexical_cast。

[startservice]

	float f;
	string str = "0.9144";
	f = atof(str.data());

[N3verL4nd]

Stringstream

[N3verL4nd]

Stringstream