C/C++里string与int的相互转换算法 .

#include <string>
using namespace std;

//将整型转换为string型
string int2str(int num)
{
    if ( num == 0 )
    {
        return "0";
    }
    
    string str="";
    
    //将num的绝对值赋予t
    int t = num>0 ? num : -1*num;
    
    while (t)
    {
        str = (char)(t%10+48)+str;
        t /= 10;
    }
    
    if ( num < 0 )
    {
        str = "-" + str;
    }
    
    return str;
}

//将string型转换为int型
int str2int(string str)
{
    int i;
    int num =0;
    int len=str.size();
    
    i = 0;
    if ( str[ 0 ] == '-' )
    {
        i = 1;
    }
    
    while ( i < len )
    {
        num = num*10 + (int)(str[i]-'0');
        i++;
    }
    
    if ( str[0]=='-' )
    {
        num *= -1;
    }
    
    return num;
}