C++练习-函数

double dist( double x1, double y1, double x2, double y2 ){double Dx,Dy;Dx=fabs(x1-x2);Dy=fabs(y1-y2);double dis;dis=sqrt(pow(Dx,2)+pow(Dy,2));return dis;
}

int sign( int x ){int res;if(x>0){res=1;}else if(x==0){res=0;}else{res=-1;}return res;
}

double fact(int n){double res=1;for(int i=1;i<=n;i++){res*=i;}return res;
}

int IsSquare(int n) {if (n < 0) return 0;int root = (int)sqrt(n);return (root * root == n) || ((root + 1) * (root + 1) == n);
}

int prime(int p){if(p<=1){return 0;}if(p == 2){return 1;  // 2是素数
    }if(p % 2 == 0){return 0;  // 偶数（除了2）都不是素数
    }for(int i=3;i*i<=p;i+=2){if(p%i==0){return 0;}}return 1;
}
int PrimeSum(int m,int n){int sum=0;for(int i=m;i<=n;i++){if(prime(i)){sum+=i;}}return sum;
}

#include <stdio.h>
void pyramid(int n){for(int i=1;i<=n;i++){for(int j=0;j<(n-i);j++){printf(" ");}for(int j=1;j<=i;j++){printf("%d",i);printf(" ");}printf("\n");} 
}

int gcd(int x, int y) { while (y != 0) {int temp = y;y = x % y;x = temp;}return x;
}

int CountDigit(int number,int digit){int res=0;char str[20];sprintf(str,"%d",number);for(int i=0;i<20;i++){if(str[i]-'0'==digit){res++;}}return res;
}

int func(int x){if(x==0){return 1;}int res=1;for(int i=1;i<x;i++){res*=i;}return res;
}double funcos(double e,double x){double res=0;int temp=0;int counter=0;while(pow(x,counter)/func(counter)<e){temp=pow(x,counter)/func(counter)<e;res+=temp*pow(-1,counter/2);counter+=2;}   return res;
}

//13.9提交后显示有错误，暂时不知道具体原因，尚未修改

int func(int x){if(x==0){return 1;}int res=1;for(int i=1;i<x;i++){res*=i;}return res;
}double funcos(double e,double x){double res=0;int temp=0;int counter=0;while(pow(x,counter)/func(counter)<e){temp=pow(x,counter)/func(counter)<e;res+=temp*pow(-1,counter/2);counter+=2;}   return res;
}