1060. Are They Equal (25)
If a machine can save only 3 significant digits, the float numbers 12300 and 12358.9 are considered equal since they are both saved as 0.123*105 with simple chopping. Now given the number of significant digits on a machine and
two float numbers, you are supposed to tell if they are treated equal in that machine.
Input Specification:
Each input file contains one test case which gives three numbers N, A and B, where N (<100) is the number of significant digits, and A and B are the two float numbers to be compared. Each float number is non-negative, no greater than 10100,
and that its total digit number is less than 100.
Output Specification:
For each test case, print in a line "YES" if the two numbers are treated equal, and then the number in the standard form "0.d1...dN*10^k" (d1>0 unless the number
is 0); or "NO" if they are not treated equal, and then the two numbers in their standard form. All the terms must be separated by a space, with no extra space at the end of a line.
Note: Simple chopping is assumed without rounding.
Sample Input 1:
3 12300 12358.9
Sample Output 1:
YES 0.123*10^5
Sample Input 2:
3 120 128
Sample Output 2:
NO 0.120*10^3 0.128*10^3
题意：将两个float型数据使用科学计数法表示，并比较两者是否相同
关键：要考虑所给输入数据的多种情况，比如 0 ， 0.0，0.0123，05.032，00.020等这种比较特殊的情况。
代码如下：
#include <iostream>
#include <fstream>
#include <cstring>
using namespace std;
ifstream fin("in.txt");
#define cin fin
int convert(const char* c,int n,char* &res)
{
int point,count;
point = count = 0;
int i=0,j=0;
while(c[i]=='0')i++; //先略去最前面的'0'
if(c[i]=='.') //形式为 (0)*.##
{
bool isBegin = false;
while(c[i]!='\0')
{
if(c[i]=='.')
{
point = 1;
}else if(c[i]!='0')
{
isBegin = true;
}
if(isBegin){
if(count<n)
{
res[count]=c[i];
count++;
}
}else
{
point--;
}
i++;
}
if(!isBegin)point=0;
}else //形式为 (0)*#.##
{
j=i;
while(c[i]!='\0')
{
if(c[i]=='.')
{
point = i-j;
}else
{
if(count<n)
{
res[count]=c[i];
count++;
}
}
i++;
}
if(point==0)//如果没有. 则等于数字个数(去掉前面的0)
point = i-j;
}
if(count<n) //如果数字个数不足，补'0'
{
i = count;
while(i<n)
{
res[i]='0';
i++;
}
}
res[n]='\0';
return point;
}
int main()
{
int n;
cin>>n;
char A[105],B[105];
cin>>A>>B;
int Ac,Bc;
char *Ares,*Bres;
Ares = new char[n+1];
Bres = new char[n+1];
Ac = convert(A,n,Ares);
Bc = convert(B,n,Bres);
if(Ac==Bc && strcmp(Ares,Bres)==0)
{
cout<<"YES 0."<<Ares<<"*10^"<<Ac<<endl;
}else
{
cout<<"NO 0."<<Ares<<"*10^"<<Ac<<" 0."<<Bres<<"*10^"<<Bc<<endl;
}
system("PAUSE");
return 0;
}