我正在尝试为C中的代码使用动态内存。我正在使用struct，但我做错了什么，但我不知道是什么。第一部分是我的header（.h）文件的一部分，在其中定义了两个结构。
第二部分是我的C（.c）文件的一部分，我在其中初始化该结构并使用它。我遇到段错误，而ddd告诉我该段。故障发生在注释后的行中：这是段。发生故障。
非常感激任何的帮助
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第一部分
======================================
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <stdlib.h>
#include <math.h>
void parseFile(FILE * fp, FILE * sketcher);
void processArgument(char argument[]);
void printOutput();
#define MAX_WORD 256
#define initial_size 17
extern const char argument[];
FILE* popen(const char*, const char*);
int pclose(FILE*);
struct pointxy {
double x;
double y;
};
struct figure{
char figureName[MAX_WORD];
struct pointxy vertices[17];
int countPoints;
};
struct figure figurehere[17];
struct figure newFigure[17];
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第二部分
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#include "draw2.h"
#include "draw2a.h"
#include "memwatch.h"
struct figure *figureHere;
void printOutput(){
printf("./draw2 started on:");
fflush(stdout);
system("date\n");
}
/*send what ever there is after the child to sketchpad(in that specific line)*/
void child (char line[], char word[], char nameFigure[], FILE * sketcher){
sscanf(line, "%s%s", word, nameFigure);
fprintf (sketcher, "%s\n", &line[6]);
}
/*I construct the struct by reading from the Figure line to the end figure line.*/
struct figure* figureFunction (FILE * fp, char line[], char word[], char figureName[], int countNumberoffigures){
double startx, starty;
int temp = 1;
sscanf(line, "%s%s%lf%lf%s", word, figureName, &startx, &starty, word);
figureHere->vertices[0].x = startx;
figureHere->vertices[0].y = starty;
strcpy(figureHere->figureName, figureName);
fgets(line, MAX_WORD - 1, fp);
int nuRead = sscanf(line, "%s", word);
int i = 1;
while (strncmp(word, "End", MAX_WORD)!=0){
if (strncmp(word, "#", MAX_WORD) == 0){
printf("%s",line);
}
if (strncmp(word, "draw", MAX_WORD) == 0){
sscanf (line, "%s%lf%lf", word, &startx, &starty);
figureHere->vertices[i].x = figureHere->vertices[i-1].x + startx;
figureHere->vertices[i].y = figureHere->vertices[i-1].y + starty;
i += 1;
}
fgets(line, MAX_WORD - 1, fp);
nuRead = sscanf(line, "%s", word);
}
figureHere->countPoints = i;
return figureHere;
}
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第三方
======================================
#include "draw2.h"
#include "draw2a.h"
#include "draw2b.h"
#include "memwatch.h"
struct figure myFigures[17];
struct figure **pointsAndname;
const char Exec_c[] = "java -jar Sketchpad.jar";
void parseFile(FILE * fp, FILE *sketcher){
char line [MAX_WORD], word [MAX_WORD], figureName [MAX_WORD];
int countNumberoffigures; //accounts to which figure in the array we are on
printOutput();
int temp = 1;
countNumberoffigures = 0;
while ( fgets(line, MAX_WORD - 1, fp) != NULL ){
int nuRead = sscanf(line, "%s", word);
if ( nuRead > 0 ){
if(strncmp(word, "Figure", MAX_WORD)==0){ //1)reads the figure, name and the two starting points
countNumberoffigures += 1; //accounts to which figure in the array we are on
pointsAndname = malloc(sizeof(struct figure*)*temp);
pointsAndname[countNumberoffigures -1] = figureFunction(fp,line, word, figureName, countNumberoffigures);
}
if(strncmp(word, "printFigure", MAX_WORD)==0){ //4)read the command printFigure, name of the figure
printFigure(fp, line, countNumberoffigures);
}
if(strncmp(word, "drawFigure", MAX_WORD)==0){ //5)read the command drawFigure and the name of the figure
drawFigure(sketcher, line, countNumberoffigures);
}
if(strncmp(word, "translate", MAX_WORD)==0){ //6)read the command translate
translate(line, sketcher, countNumberoffigures);
}
if(strncmp(word, "child", MAX_WORD)==0){ //7)reads command child and the name of the figure
child(line, word, figureName, sketcher);
}
if(strncmp(word, "#", MAX_WORD)==0){ //8)reads the whole line until the \n
printf(line);
//printf("ani po\n");
}
if(strncmp(word, "end", MAX_WORD)==0){
fprintf (sketcher, "end\n");
//printf("ani po\n");
}
if(strncmp(word, "rotate", MAX_WORD)==0){
rotate(line, sketcher, countNumberoffigures);
}
}
}
}
void processArgument(char argument[]){
FILE *sketcher;
FILE *fp;
fp = fopen (argument, "r");
sketcher = popen(Exec_c, "w");
if (sketcher == NULL){
printf ("Could not open pipe to %s\n", argument);
}else{
parseFile(fp, sketcher);
fclose(fp);
if (pclose(sketcher) == -1){
fprintf(stderr, "draw_line error: couldn't close pipe to %s.\n", Exec_c);
exit(EXIT_FAILURE);
}
}
}
int main (int argc, char *argv[]){
int i;
if ( argc < 2 ){
printf ("%s\n", "0 comment(s)");
}else{
for (i = 1; i < argc; i++){
processArgument(argv[i]);
}
}
//int *a = malloc(sizeof(int));
return 0;
}
最佳答案
在头文件中，您声明了一个静态的数字数组，其中包括：
struct figure figurehere[17];
但是，在实现文件（* .c）中，您正在使用以下命令创建指向“图”的单独指针
struct figure *figureHere;
现在，从技术上讲，它们是完全独立的，并且
figurehere和figureHere都可以在您的实现文件中访问，因为C区分大小写...但是，我想这可能对您而言不是故意的，最后一种做法可能被认为是不好的做法，因为在快速阅读代码时可能会造成混淆或误导。我建议，如果您希望它们是完全独立的变量，则应为它们命名明显不同。但是，在前面的注释中所说的是正确的答案：您正在声明一个指针
figureHere，并且无需初始化就可以使用它。....我在假设您要使
figureHere（大写H）指向figurehere（低H）的前提下写出了一个解释，但是后来我意识到这个问题专门提到了malloc。不幸的是，malloc甚至没有出现在您的代码中，因此我不确定用法是“错误的”，只是没有使用。代码丢失了吗？还是您在使用malloc正确创建figure指向figureHere指向时遇到麻烦？编辑/附加：
重读我注意到你特别说的问题
第一部分是我的一部分
header（.h）文件，其中我定义了两个
我的结构。
这确实使我相信您打算将
figurehere和figureHere设置为同一数组。为此，您有几种选择：1）删除
figureHere，直接使用figurehere。因为您在这里已将figurehere声明为全局变量（许多人会告诉您这很不好，但这是一个完全不同的主题），所以您可以直接访问它而无需任何指针。2）初始化
figureHere指向figurehere。您只需将声明更改为struct figure *figureHere = figurehere;关于c - 错误使用了malloc，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/4161901/