Question

一个c++编程，用到了atoi函数，错误显示无法转变类型。

#include <stdlib.h>
#include <vector>
#include <string>
#include <fstream>
#include <sstream>
#include <iomanip>
using namespace std;
int main()
{
ifstream in1("c:\\508.txt");
ofstream out1("c:\\out.txt");
ofstream out2("c:\\out00.txt");
//将所有出现的城市入栈
vector<string> ss1;
ss1.clear();
int i,j=0,j1=0,h3=0,h1,h2,js=0;
string s,s1,s2,s3,c1,c2,c3;

while(getline(in1,s))

{i=0; j++;
istringstream sin(s);
for(string s9;sin>>s9;)
{
i++;
if(i==1) c1=s9;
else if(i==2) c2=s9;
else if(i==3) c3=s9;
else { out1<<"计算出错！！请检查！"; break;}

ifstream in11("c:\\508.txt"); j1=0;
while(getline(in11,s2))
{ j1++; if(j1>j) if(s2.find(c2,0)!=-1) if(s2.find(c3,0)!=-1)
{
out2<<s<<"______"<<s2<<endl;
js=0; h1=-1; h2=-1; h3=-1;
istringstream sin(s2);
for(string s9;sin>>s9;) { js++; if(js==1) {int h1=atoi(s9); int h2=atoi(c1); int h3=h1+h2; break;} }
if(js==1) {out1<<h3<<" "<<c2<<" "<<c3<<endl; out2<<h3<<" "<<c2<<" "<<c3<<endl; break;}

}

}

}

}

return 0;

}
我原始的数据比如说是：61 上海大学 山东大学。在其他行中可能还存在20 山东大学上海大学。我要把两个的数字相加，只保留一行，将出现的第二行去除。
提示错误如下：
Cpp1.cpp(42) : error C2664: 'atoi' : cannot convert parameter 1 from 'class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >' to 'const char *'
No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called
C:\Documents and Settings\Administrator\桌面\Cpp1.cpp(42) : error C2664: 'atoi' : cannot convert parameter 1 from 'class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >' to 'const char *'
No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called
Error executing cl.exe.
我又修改了一下程序，最后的地方变成了 js=0; h1=-1; h2=-1; h3=-1;
istringstream sin(s2);
for(string s9;sin>>s9;) { js++; if(js==1) {int h1=atoi(s9.c_str()); int h2=atoi(c1.c_str());

int h3=h1+h2; out1<<h3<<" "<<c2<<" "<<c3<<endl; out2<<h3<<" "<<c2<<" "<<c3<<endl; }可是光有数字没汉字，什么情况呀

Answer 1

String类是一个宏定义，相当于basic_string<char, char_traits<char>, allocator<char> >，而atoi函数的形参是指针常量，也可以说是一个数组的数组名，形参类型都不同，当然不行了

Answer 2

int h1=atoi(s9); 改为 int h1=atoi(s9.c_str());