第一关：快递费用计算

#include<stdio.h>
int main(void)
{  
  /*********Begin*********/
  int area; // 地区
  float weight; // 重量
  float beginWeight = 1.0; // 起重量
  float price = 0.0; // 价格
  scanf("%d,%f",&area,&weight);
  if(area == 0){ // 同城
    if(weight < beginWeight){
      price = 10;
    }else{
      if((int)weight != weight){
        price = 10 + ((int)(weight-beginWeight)+1)*3;
      }else{
        price = 10 + (weight-beginWeight)*3;
      }
    }
  }else if(area == 1){
    if(weight < beginWeight){
      price = 10;
    }else{
      if((int)weight != weight){
        price = 10 + ((int)(weight-beginWeight)+1)*4;
      }else{
        price = 10 + (weight-beginWeight)*4;
      }
    }
  }else if(area == 2){
    if(weight < beginWeight){
      price = 15;
    }else{
      if((int)weight != weight){
        price = 15 + ((int)(weight-beginWeight)+1)*5;
      }else{
        price = 15 + (weight-beginWeight)*5;
      }
    }
  }else if(area == 3){
    if(weight < beginWeight){
      price = 15;
    }else{
      if((int)weight != weight){
        price = 15 + ((int)(weight-beginWeight)+1)*6.5;
      }else{
        price = 15 + (weight-beginWeight)*6.5;
      }
    }
  }else if(area == 4){
    if(weight < beginWeight){
      price = 15;
    }else{
      if((int)weight != weight){
        price = 15 + ((int)(weight-beginWeight)+1)*10;
      }else{
        price = 15 + (weight-beginWeight)*10;
      }
    }
  }else{
    printf("Error in Area\n");
  }
  printf("Price: %.2f",price);
  /*********End**********/ 
  return 0;
}

第二关：计算一元二次方程根

#include<stdio.h>
// 加入开根号的数学头文件
#include<math.h>
int main(void)
{  
  /*********Begin*********/
  float a,b,c,x1,x2;
  printf("Please enter the coefficients a,b,c:\n");
  scanf("%f,%f,%f",&a,&b,&c);
  // 实根需要满足的条件 b^2-4ac>=0并且a!=0
  if(b*b-4*a*c>=0&&a!=0){
    // sqrt() 可以用来开根号
    x1 = (-b + sqrt(b*b-4*a*c))/(2*a);
    x2 = (-b - sqrt(b*b-4*a*c))/(2*a);
    printf("x1=%.4f, x2=%.4f\n",x1,x2);
  }else {
    printf("error!");
  }
  /*********End**********/ 
  return 0;
}

第三关：产品信息格式化

#include<stdio.h>
int main(void)
{  
  /*********Begin*********/
  int number;
  float price;
  int month;
  int day;
  int year;
  printf("Enter item number:");
  scanf("%d",&number);
  printf("\nEnter unit price:");
  scanf("%f",&price);
  printf("\nEnter purchase date (mm/dd/yy):");
  scanf("%d/%d/%d",&month,&day,&year);
  printf("\nItem Unit Purchase\n");
  printf("%-9d$ %-9.2f%02d%02d%02d\n",number,price,month,day,year);
  /*********End**********/ 
  return 0;
}