[HTDP]<3.1 函数的复用>
debug_pos.h
/* ************************************************************************
* Filename: debug_pos.h
* Description: Debugging error message positioning
* Version: 1.0
* Created: 2014-11-14 22:55:26
* Revision: none
* Compiler: gcc
* Author: lsgx
* Company: lsgx
* ************************************************************************/
#ifndef _DEBUG_POS_H_
#define _DEBUG_POS_H_
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <time.h>
#define MAX_TITLE_LEN 64
#define MAX_DEBUG_LEVEL 6
#define DEBUG_POS_LOG "debug_pos.log"
#define DEBUG_UNKNOWN_TITLE "debug_unknown"
#define DEBUG_TEST_TITLE "debug_test"
#define DEBUG_INFO_TITLE "debug_info"
#define DEBUG_WARN_TITLE "debug_warn"
#define DEBUG_ERROR_TITLE "debug_error"
#define DEBUG_QUITE_TITLE "debug_quite"
#define DEBUG_UNKNOWN_LEVEL 5
#define DEBUG_TEST_LEVEL 4
#define DEBUG_INFO_LEVEL 3
#define DEBUG_WARN_LEVEL 2
#define DEBUG_ERROR_LEVEL 1
#define DEBUG_QUITE_LEVEL 0
#define DEBUG_LIMIT_TITLE DEBUG_WARN_TITLE
#define DEBUG_LIMIT_LEVEL DEBUG_WARN_LEVEL
struct DEBUG_STR {
char title[MAX_TITLE_LEN];
int level;
};
struct DEBUG_STR DEBUG_STR_ITEM[MAX_DEBUG_LEVEL] = {
{DEBUG_QUITE_TITLE, DEBUG_QUITE_LEVEL},
{DEBUG_ERROR_TITLE, DEBUG_ERROR_LEVEL},
{DEBUG_WARN_TITLE, DEBUG_WARN_LEVEL},
{DEBUG_INFO_TITLE, DEBUG_INFO_LEVEL},
{DEBUG_TEST_TITLE, DEBUG_TEST_LEVEL},
{DEBUG_UNKNOWN_TITLE, DEBUG_UNKNOWN_LEVEL},
};
static void system_time(char * time_str)
{
time_t now = time((time_t *)NULL);
struct tm * timenow = localtime(&now);
sprintf(time_str, "%4d-%02d-%02d %02d:%02d:%02d",
timenow->tm_year + 1900,
timenow->tm_mon + 1,
timenow->tm_mday,
timenow->tm_hour,
timenow->tm_min,
timenow->tm_sec);
}
// #define DEBUG_POS_NO
#ifndef DEBUG_POS_NO
#define debug_pos(DEBUG_TITLE, ...) do { \
for (unsigned int i = 0; i < (sizeof(DEBUG_STR_ITEM)/sizeof(DEBUG_STR_ITEM[0])); i++) { \
if (strncmp(DEBUG_TITLE, DEBUG_STR_ITEM[i].title, MAX_TITLE_LEN) == 0) { \
FILE * debug_pos_fp = NULL; \
debug_pos_fp = fopen(DEBUG_POS_LOG, "a+"); \
char time_str[20] = {'\0'}; \
system_time(time_str); \
fprintf(debug_pos_fp, "[%s] [%s] [file_name: %s, line_no: %d, function_name: %s]\n\t>>>>", \
DEBUG_TITLE, time_str, __FILE__, __LINE__, __FUNCTION__); \
fprintf(debug_pos_fp, __VA_ARGS__); \
fputc('\n', debug_pos_fp); \
if (DEBUG_STR_ITEM[i].level < DEBUG_LIMIT_LEVEL) { \
fprintf(debug_pos_fp, "%s", "\t>>>>****** debug exit abort process ******\n"); \
fclose(debug_pos_fp); \
abort(); \
} \
fclose(debug_pos_fp); \
} \
} \
} while(0)
#else
#define debug_pos(DEBUG_TITLE, ...) NULL
#endif // DEBUG_POS_NO
#define debug_asert(condition, ...) do { \
if (condition) \
NULL; \
else \
debug_pos(DEBUG_ERROR_TITLE, __VA_ARGS__); \
} while(0)
#endif // _DEBUG_POS_H_
profit.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <time.h>
// #define DEBUG_POS_NO
#include "debug_pos.h"
int attendanees_calc(float ticket_price)
{
return (120 + 15 / 0.1 * (5 - ticket_price));
}
float revenue_calc(float ticket_price)
{
int attendanees = 0;
attendanees = attendanees_calc(ticket_price);
debug_pos(DEBUG_INFO_TITLE, "attendanees is [%d]", attendanees);
return (attendanees * ticket_price);
}
float cost_calc(float ticket_price)
{
int attendanees = 0;
attendanees = attendanees_calc(ticket_price);
debug_pos(DEBUG_INFO_TITLE, "attendanees is [%d]", attendanees);
// return (180 + 0.4 * attendanees);
return ((0.4 + 1.5) * attendanees);
}
float profit_calc(float ticket_price)
{
float revenue = 0.0;
float cost = 0.0;
revenue = revenue_calc(ticket_price);
cost = cost_calc(ticket_price);
debug_pos(DEBUG_INFO_TITLE, "revenue is [%f], cost is [%f]", revenue, cost);
return (revenue - cost);
}
int main(int argc, char *argv[])
{
char ch = '\0';
char status = '\0';
float ticket_price = 0.0;
float profit = 0.0;
while (status != 'N' && status != 'n') {
printf("请输入票价 : ");
fflush(stdout);
scanf("%f", &ticket_price);
while((ch = fgetc(stdin)) != EOF && ch != '\n')
NULL;
debug_pos(DEBUG_INFO_TITLE, "ticket_price is [%f]", ticket_price);
profit = profit_calc(ticket_price);
printf("profit is [%f]\n", profit);
printf("是否继续[是:Y/y 否:N/n] : ");
fflush(stdout);
scanf("%c", &status);
while((ch = fgetc(stdin)) != EOF && ch != '\n')
NULL;
}
return 0;
}
profit.scm
#lang racket/base ;; 合约 : profit : number -> number ;; 用途 : 对于给定 ticket-price, 利润是收入和成本之差 (define (profit ticket-price) (- (revenue ticket-price) (cost ticket-price))) ;; 合约 : revenue : number -> number ;; 用途 : 对于给定 ticket-price, 计算收入 (define (revenue ticket-price) (* (attendanees ticket-price) ticket-price)) ;; 合约 : cost : number -> number ;; 用途 : 对于给定 ticket-price, 计算成本 (define (cost ticket-price) ;;(+ 180 (* 0.4 (attendanees ticket-price)))) (* (+ 0.4 1.5) (attendanees ticket-price))) ;; 合约 : attendanees : number -> number ;; 用途 : 对于给定 ticket-price, 计算观众人数 (define (attendanees ticket-price) (+ 120 (* (/ 15 0.10) (- 5.00 ticket-price))))
当播放电影的成本是固定180时, 根据题意得出方程式为： y = (-150) * x^2 + 930 * x - 528
因为 y = a * x^2 + b * x + c 中 a = (-150) < 0, 开口朝下, 存在最大值。
根据对称轴公式直线 x = -b/2a = -(930 / (2 * (-150))) = 3.1, 此时最大值为 y = 913.5
当播放电影的成本是浮动时, 根据题意得出方程式为： y = (-150) * x^2 + 1155 * x - 1653
因为 y = a * x^2 + b * x + c 中 a = (-150) < 0, 开口朝下, 存在最大值。
根据对称轴公式直线 x = -b/2a = -(1155 / (2 * (-150))) = 3.85, 此时最大值为 y = 570.375
temconv.scm
#lang racket/base ;; 合约 : Celsius->Fahrenheit : number -> number ;; 用途 : 对于给定 Ctemp, 将摄氏温度转化为华氏温度 (define C2F-DIFF 32) (define C2F-SCALE (/ 9 5)) (define (C2F Ctemp) (+ (* Ctemp C2F-SCALE) C2F-DIFF)) ;; 合约 : Fahrenheit->Celsius : number -> number ;; 用途 : 对于给定 Ftemp, 将华氏温度转化为摄氏温度 (define F2C-DIFF 32) (define F2C-SCALE (/ 5 9)) (define (F2C Ftemp) (* (- Ftemp F2C-DIFF) F2C-SCALE)) ;; 合约 : FCF : number -> number ;; 用途 : 对于给定 Ftemp, 将华氏温度转化为摄氏温度再转化为华氏温度 (define (FCF Ftemp) (C2F (F2C Ftemp))) ;; 合约 : CFC : number -> number ;; 用途 : 对于给定 Ctemp, 将摄氏温度转化为华氏温度再转化为摄氏温度 (define (CFC Ctemp) (F2C (C2F Ctemp)))