帮助理解结构 [英] Help on understanding Structs

问题描述

我将在即将到来的星期五进行考试，我的教授告诉我们，这将是基于这个项目的b $ b。我很难理解这个

计划，例如，如果我想将用户输入的所有总热量添加到用户输入中。确定哪种食物含有最大的卡路里。

我如何开始修改程序以便完成我列出的内容

以上。谢谢


#include< stdio.h>

#include< stdlib.h>


typedef struct {

char * name;

int calories;

int group;

} FOOD;


void getFood（FOOD foods []，int i）{

FOOD newFood;

void * characters = malloc（81 * sizeof（ char））;


printf（&\\; \ n请输入所要求的信息：\ n"）;

printf（" for food item％ d，什么是\ n，i + 1）;

printf（" name？"）;

得到（字符）; //注意fgets更好！

newFood.name = characters;


printf（" calories / serving？"）;

scanf（"％d"，&（newFood.calories））;


printf（" food group？"）;

scanf（"％d"，&（newFood.group））;

printf（" \ n"）;

foods [i] = newFood ;


} //结束getFood //注意：结构是和左值!!


void dump（FOOD foods []，int n）{

int i;

for（i = 0; i< n; i ++）{

printf（" Food％d是：\ n"，i + 1）;

printf（" name：％s \ n"，foods [i] .name）;

printf （卡路里：％d \ n，食物[i] .calories）;

printf（" group＃：％d \ n"，foods [i] .group）;

printf（" \ n"）;

} //结束

} //结束转储


int main（）{

int num; //输入的食物数量

int i;

char dum [81];


printf（" \\\
How你会输入很多食物吗？"）;

scanf（"％d"，& num）;


食物食品[num];

for（i = 0; i< num; i ++）{

得到（dum）; //注意：这就是因为SCANF

getFood（食品，我）;

} //结束


dump（foods，num）;

返回0;

} //结束主

I will have a exam on the oncoming friday, my professor told us that it
will base upon this program. i am having troubles understanding this
program, for example what if i want to add all the total calories that
the user input together. determine which food has the largest calories.
how do i start to modifiy the program inorder to do the things i listed
above. thanks

#include <stdio.h>
#include <stdlib.h>

typedef struct {
char *name;
int calories;
int group;
} FOOD;

void getFood(FOOD foods[ ], int i ) {
FOOD newFood;
void *characters = malloc(81*sizeof(char));

printf("\nPlease enter the requested information:\n");
printf(" for food item %d, what is\n", i+1);
printf(" the name? ");
gets( characters); // NOTE fgets IS BETTER!
newFood.name = characters;

printf(" calories/serving? ");
scanf("%d", &(newFood.calories));

printf(" food group? ");
scanf("%d", &(newFood.group));
printf("\n");
foods[i] = newFood;

} // end getFood // note:a struct is and lvalue !!

void dump( FOOD foods[ ] , int n ) {
int i;
for(i=0; i<n; i++ ) {
printf("Food %d is: \n", i+1);
printf(" name : %s\n", foods[i].name);
printf(" calories: %d\n", foods[i].calories);
printf(" group # : %d\n", foods[i].group);
printf("\n");
} // end for
} // end dump

int main( ) {
int num; // number of foods entered
int i;
char dum[81];

printf("\nHow many foods will you enter? ");
scanf("%d", &num);

FOOD foods[num];
for( i=0; i<num; i++ ) {
gets(dum); //NOTE: THIS IS HERE BECAUSE OF SCANF
getFood( foods, i );
} // end for

dump( foods, num);
return 0;
} // end main

推荐答案

是这样的：


// ......

int total_calories;

int maxcalories ;

char maxcaloriesname [81]

// ......

total_calories = 0;

maxcalories = 0;

strcpy（maxcaloriesname，" no"）;

// ......


食物食品[num];

for（i = 0; i< num ++）{


getFood（食物，i）;

// .......

total_calories + =食物[i] .calories;

if（食物[i] .calories> maxcalories）< br $>
{

maxcalories = foods [i] .calories;

strcpy（maxcaloriesname，foods [i] .name）;

}


} //结束

// .....

like this:

//......
int total_calories;
int maxcalories;
char maxcaloriesname[81]
//......
total_calories=0;
maxcalories=0;
strcpy(maxcaloriesname,"no");
//......

FOOD foods[num];
for( i=0; i<num; i++ ) {

getFood( foods, i );
// .......
total_calories+=foods[i].calories;
if(foods[i].calories>maxcalories)
{
maxcalories=foods[i].calories;
strcpy(maxcaloriesname,foods[i].name);
}

} // end for
//.....

Bail写道：

我将在即将到来的星期五进行考试，我的教授告诉我们，这将基于这个计划。


我已经掀起了一些代码，这些代码可以正常工作，并且仅将其粘贴到

发现，它是星期四！b $ b星期四！ />
i我很难理解这个
程序，例如，如果我想添加用户输入的所有总卡路里，该怎么办。确定哪种食物含有最大的卡路里。
我如何开始修改程序，以便完成上面列出的内容。谢谢

I will have a exam on the oncoming friday, my professor told us that it
will base upon this program.
I had whipped up some code, which works, and pasted it only to
discover, its
thursday!
i am having troubles understanding this
program, for example what if i want to add all the total calories that
the user input together. determine which food has the largest calories.
how do i start to modifiy the program inorder to do the things i listed
above. thanks

[太多我觉得我不得不评论的东西......]


1.不要使用获取。这很危险。 GIYF。

2.使用scanf的交互式输入很棘手。搜索档案，

的东西

喜欢scanf + string + input + pete。 （皮特碰巧发布了一些

代码我非常喜欢）

3.了解qsort（）。这里有一些提示：你需要类似

....


int calcmp（const void * l，const void * r）< br $>
{

const FOOD * left = l;

const FOOD * right = r;

if（left- left- >卡路里>右 - &>卡路里）

返回1;

/ *填空白... * /

}


4.你说你遇到了麻烦。大概，不是代码你

粘贴。

如果你理解你粘贴的代码，家庭作业应该很容易

：）

星期五见ya''。

[just too many things I felt i had to comment on so ... ]

1. Don''t use gets. Its dangerous. GIYF.
2. Interactive input with scanf is tricky stuff. Search the archive,
with something
like "scanf + string + input + pete ". (pete happens to post some
code I really like)
3. Learn about qsort(). Here''s some hint: you will need something like
....

int calcmp( const void *l, const void *r )
{
const FOOD *left = l;
const FOOD *right = r;
if ( left->calories > right->calories )
return 1;
/* fill in the blanks ... */
}

4. You said you''re having trouble. Presumably, not with the code you
pasted.
If you understand the code you pasted, the homework should be easy
:)
See ya'' on friday.

Suman写道：

Suman wrote:

2.互动使用scanf输入是棘手的事情。搜索存档，
像
scanf + string + input + pete。 （皮特碰巧发布一些我非常喜欢的代码）

2. Interactive input with scanf is tricky stuff. Search the archive,
with something
like "scanf + string + input + pete ". (pete happens to post some
code I really like)

这种使用scanf的方式主要由Dan Pop推广。

Dan Pop倾向于非常准确，但是......


如果我要说他有一个磨砺的个性，

它不会至少让我感到惊讶，

如果他回答逻辑上的反驳

他的性格如何没有磨损

我必须如何精神上有缺陷

甚至想到这样的事情。


-

pete

That way of using scanf, was primarily promoted by Dan Pop.
Dan Pop tended to be very accuarate, but was ...

If I were to say that he had an abrasive personality,
it would not surprise me in the least,
if he were to reply with a logical rebuttal
of how his personality was not abrasive
and how I must be mentally deficient
for even thinking something like that.

--
pete

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