复利计算

#include<stdio.h>
#include<math.h>

double principal=0,mount=0;
int year=0;
int n=1;
double rate;

void danli(){
    printf("请输入的本金：");
    scanf("%lf",&principal);
    printf("请输入年限：");
    scanf("%d",&year);

    printf("请输入年利率：");
    scanf("%lf",&rate);
    mount=principal+principal*rate*year;
    printf("本息为：%.2lf\n",mount);


}

void fuli(){

    printf("请输入本金：");
    scanf("%lf",&principal);
    printf("请输入年限：");
    scanf("%d",&year);
    printf("请输入年利率：");
    scanf("%lf",&rate);
    printf("请输入年复利次数:");
    scanf("%d",&n);
    rate=pow((1+rate/n),n)-1;
    mount=principal*pow((1+rate),year);
    printf("本息为：%.2lf\n",mount);

}

void principaljisuan(){
    printf("请输入期望的收益：");
    scanf("%lf",&mount);  
    printf("请输入年限：");
    scanf("%d",&year);
    printf("请输入年利率：");
    scanf("%lf",&rate);
    printf("请输入年复利次数:");
    scanf("%d",&n);
    rate=pow((1+rate/n),n)-1;
    principal=mount/pow((1+rate),year);
    printf("输出所需本金为：%.2lf\n",principal);

}

main(){
    int num=0;
printf("|----------------------------------------------------------|\n");
printf("|      1.复利计算                                      |\n");
printf("|      2.单利计算                                      |\n");
printf("|      3.计算本金                                      |\n");
printf("|----------------------------------------------------------|\n");
printf("请输入选择：");
scanf("%d",&num);
switch(num){
case 1:
    fuli(); 
    break;
case 2:
   danli();
    break;
case 3:
    principaljisuan();
default:
    return 0;

}

}