题目地址:http://ac.jobdu.com/problem.php?pid=1514
给定一个double类型的浮点数base和int类型的整数exponent。求base的exponent次方。
输入可能包含多个测试样例。
对于每个输入文件,第一行输入一个整数T,表示测试案例的数目,接下来的T行每行输入一个浮点数base和一个整数exponent,两个数中间用一个空格隔开。
对应每个测试案例,
输出一个浮点数代表答案,保留两位小数即可。
5 1.0 10 0.0 -5 1.0 0 1.2 5 2.0 -1
1.00e+00f INF 1.00e+00f 2.49e+00f 5.00e-01f
#include <stdio.h> #include <math.h> #include <stdlib.h> double PowerWithUnsignedExponent (double base, unsigned int exponent){ if (exponent == 0) return 1.0; if (exponent == 1) return base; double ans = PowerWithUnsignedExponent (base, exponent >> 1); ans *= ans; if (exponent & 0x01 == 1){ ans *= base; } return ans; } double Power (double base, int exponent){ double ans; unsigned int uexponent; if ((base == 0) || (base == 0 && exponent < 0)) return 0.0; uexponent = (unsigned int)abs (exponent); ans = PowerWithUnsignedExponent (base, uexponent); if (exponent < 0) ans = 1.0 / ans; return ans; } int main(void){ int T; double base; int exponent; double ans; double zero = 0.0; while (scanf ("%d", &T) != EOF){ while (T-- != 0){ scanf ("%lf%d", &base, &exponent); ans = Power (base, exponent); if (ans != 0.0) printf ("%.2ef\n", ans); else if (base == 0.0 && exponent >= 0) printf ("%.2ef\n", zero); else printf ("INF\n"); } } return 0; }