#include#include#definePI3.141592653longfactorial(intn);doublesin1(doublex);intmain(void){intx=30;doubleresult=sin1(x);printf("sin(%d°)=%f\n",x,result);printf("Bye\n");return0;}/***求阶乘*@paramn[description]*@return[description]*/longfactorial(intn){if(n==1)return1;elsereturn(n*factorial(n-1));}/***计算sin(x),因为sin在math.h中定义了,所以这里方法名用sin1。*sin(x)=x^1/1!-x^3/3!+x^5/5!-x^7/7!+...*把表达式中的-号,转换为+号,方便计算。*sin(x)=1*x^1/1!+(-1)*x^3/3!+1*x^5/5!+(-1)*x^7/7!+...*@paramx角度*@returnsin(x)*/doublesin1(doublex){intflag1=1;//表示符号位intflag2=1;//表示指数和阶乘,每次+2.doublexf;//把输入的角度转成弧度,180度=π弧度=>1度=π/180弧度。doubletemp;//保存每一项计算的结果doublesum=0;//保存最终结果xf=PI/180.0*x;do{temp=flag1*pow(xf,flag2)/factorial(flag2);sum+=temp;flag1*=-1;flag2+=2;}while(fabs(temp)-0.000001>=0);//判断最后一项的绝对值小于10的负6次方returnsum;} |