C语言基础之数据结构

1.32 换成数字23

# include<stdio.h> //编译预处理指令
# include <math.h>
# define pi 3.1415926  //定义不变常量
int convert(int num);
char ABC(char a);
double sum(double a,double b, double c);
double area(double a,double b, double c);
double num(double a,double b ,double c );
double interest_rate_current(double principal);
double interest_rate_regular(double principal);
double interest_rate_halfyear(double principal);
int main(){ //定义主函数//假定本金为1000，求一年后的存款+利息double principal = 1000.00;double  p1 = interest_rate_current(principal);double p2 = interest_rate_regular(principal);double p3 = interest_rate_halfyear(principal);printf("一年后活期存款为：%.2f,定期存款为：%.2f,半年存款为：%.2f \n",p1,p2,p3);// //录入三个浮点数：// float a2,b2,c2;// printf("please input 3 :");// scanf(" %f,%f,%f",&a2,&b2,&c2);// printf( " %f, %f, %f",a2,b2 ,c2 );// double a1 = 3.67;// double b1= 5.22;// double c1 = 6.45;// printf("a = %f   b = %f   c = %f  周长是：%f \n",a1,b1,c1,sum(a1,b1,c1));// printf("a = %f   b = %f   c = %f  面积是：%f \n",a1,b1,c1,area(a1,b1,c1));// char c = 'B' ;// char d = ABC(c);// printf("小写字母是: %c \n",d);// // int outnumber = convert(32);// // printf("结果是:%d \n",outnumber);}
//计算利率，一年的活期利率为：0.0036，一年的定期利率：0.0225，半年的利率为0.0198
double interest_rate_current(double principal){double p1 = principal *(1+0.0036);return p1;
}
double interest_rate_regular(double principal){double p2 = principal * (1+0.0225);return p2;
}
double interest_rate_halfyear(double principal){double p3 = (principal * (1+ 0.0210/2))*(1 + 0.0210/2);return p3;
}//对给定任意三角形的边长，计算面积
double area(double a,double b, double c){double s = (a+b+c)/2;double areaThree = sqrt(s*(s-a)*(s-b)*(s-c));return areaThree;
}
//对给定任意三角形的边长，计算周长
double sum(double a,double b, double c){double sumThree = a+b+c;return sumThree;}
//对给的字母进行小写转换
char ABC(char a){char b = a+32;return b;}
//对一个两位的数字进行位置调换
int  convert(int  num){int num2 ;num2= num/10+((num%10)*10);return num2;
}