3.6 PAT A1073 Scientific Notation (20分)(科学计数法——字符串处理）

1073 Scientific Notation (20分)

Scientific notation is the way that scientists easily handle very large numbers or very small numbers. The notation matches the regular expression [+-][1-9].[0-9]+E[+-][0-9]+ which means that the integer portion has exactly one digit, there is at least one digit in the fractional portion, and the number and its exponent's signs are always provided even when they are positive.

Now given a real number A in scientific notation, you are supposed to print A in the conventional notation while keeping all the significant figures.

Input Specification:

Each input contains one test case. For each case, there is one line containing the real number A in scientific notation. The number is no more than 9999 bytes in length and the exponent's absolute value is no more than 9999.

Output Specification:

For each test case, print in one line the input number A in the conventional notation, with all the significant figures kept, including trailing zeros.

Sample Input 1:

+1.23400E-03

 

Sample Output 1:

0.00123400

 

Sample Input 2:

-1.2E+10

 

Sample Output 2:

-12000000000

题意为将以科学计数法形式给出的数字以对应的普通形式输出。此题有几个注意点：1符号的处理；2指数与基数的分别处理；3小数点的浮动。需要分情况一一讨论。

参考代码：

#include 
#include 
char num[10000];
char exp[1000];
char str[10000];
int main()
{
	while(scanf("%s",str)!=EOF)
	{
		int len =strlen(str);
		int cn=0,ce=0;
		if(str[0]=='-')
			printf("-"); 
		int i=0;
		for(i;i='0'&&str[i]<='9')
				num[cn++]=str[i]; //更新基数 
		}
		
		int n=0; //指数大小 
		exp[ce++]=str[++i];
		for(++i;i0 
		{
			if(n+1>=cn) //指数大于对应基数位数，需要输出多余的0 
			{
				for(int j=0;j