c++语言程序设计(郑莉)第四版第三章例子实现
例3-1 求 x 的 n 次方
#includeusing namespace std; double power(double x,int y) { double val = 1; for( ;y>=1 ;y--) val*=x; return val; } int main() { double x; int y; cout<<"please enter x and y:"< >x>>y; cout<<"x power y is "< 例3-2 二进制转化为十进制
#includeusing namespace std; int power(int x,int y) { int val = 1; for( ;y>=1 ;y--) val*=x; return val; } int main() { int val = 0; cout<<"Enter an 8 bit binary number:"; for(int i = 7; i >= 0; i--) { char ch; cin>>ch; if(ch == '1') { val += power(2,i); } } cout<<"Decimal number is "< 例3-3 求 PI 的值
#includeusing namespace std; double arctan(double x) { double sqr = x*x; double e = x; double r = 0; int i = 1; while(e/i > 1e-15) { double f = e/i; r = (i%4==1)?r+f:r-f; e = e*sqr; i+=2; } return r; } int main() { double PI = 16 * arctan(1.0/5) - 4 * arctan(1.0/239); cout<<"PI is "< 例3-4 寻找特殊的 m