C 如何在游戏板（2d阵列）内打印随机单词？
我正在用C语言和Cygwin终端编写一个打字游戏 我从一个.txt文件中读取了1000个单词，然后我随机打印了一个单词。我需要在2d数组框“gameboard”中打印这个随机单词 如何在框内打印随机单词？ 单词需要显示在框的顶行的随机水平位置 注：当我说方框时，我指的是由破折号和星号组成的20（高）乘80（宽）的方框 任何帮助都将不胜感激。事先非常感谢C 如何在游戏板（2d阵列）内打印随机单词？,c,arrays,pointers,struct,function-pointers,C,Arrays,Pointers,Struct,Function Pointers,我正在用C语言和Cygwin终端编写一个打字游戏 我从一个.txt文件中读取了1000个单词，然后我随机打印了一个单词。我需要在2d数组框“gameboard”中打印这个随机单词 如何在框内打印随机单词？ 单词需要显示在框的顶行的随机水平位置 注：当我说方框时，我指的是由破折号和星号组成的20（高）乘80（宽）的方框 任何帮助都将不胜感激。事先非常感谢 #include <stdio.h> #include <stdlib.h> #include <string.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <time.h>
void main(){
int g, h; //index for use in for loop
//creates box
const int boxLength = 20;
const int boxWidth = 75;
char box[boxLength][boxWidth];
for(int g = 0; g < boxLength; g++){
for(int h = 0; h < boxWidth; h++){
if(g == 0 || g == boxLength - 1)
box[g][h] = '-';
else if(h == 0 || h == boxWidth - 1)
box[g][h] = '|';
else
box[g][h] = ' ';
}
}
FILE *myFilePointer2 = fopen("wordList.txt", "r");
srand(time(0));
int size = 1000;
if(myFilePointer2 == NULL){
printf("Unable to open file wordList.txt");
exit(0);
}
char** words = (char**)malloc(sizeof(char**)*size); //2d pointer array, dynamically allocated, to store words from text file
char wordBankArray[1050];//wordBankArray
int wordQuantity = 0;
while(fgets(wordBankArray, 1050, myFilePointer2) != NULL){// read data from myFilePointer line by line and store it into words array
words[wordQuantity] = (char*)malloc(sizeof(char)*(strlen(wordBankArray)+1)); //dynamically allocates memory for words array
strcpy(words[wordQuantity], wordBankArray); //copying words from text file to wordBankArray
wordQuantity++;
}
printf("Randomly generated word from .txt file: ");
int index = rand()%wordQuantity; // psuedo randomly generates an index in range of 0 to wordQuantity)
printf("%s\n", words[index]); //prints randomly generated word from index
for(int g = 0; g < boxLength; g++){ //prints 2d box
for(int h = 0; h < boxWidth; h++){
printf("%c", box[g][h]);
}
printf("\n");
fclose(myFilePointer2); //close file for reading
}
}
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void main（）{
int g，h；//用于for循环的索引
//创建长方体
const int boxLength=20；
const int boxWidth=75；
字符框[boxLength][boxWidth]；
对于（int g=0；gfor（int g=0；gfclose（）中执行fclose（）
（关闭文件boxLength
的次数）
如果您正在定义const int…
，那么您正在创建一个2D VLA（可变长度数组），这很好，但是如果边界在编译时之前已知，请使用#define
声明常量，并避免C89/90中不存在的VLA，该VLA在C99中引入，并成为C11中的可选功能
您还应该将-Wshadow
添加到编译字符串中，以隐藏变量：
int g, h; //index for use in for loop
for(int g = 0; g < boxLength; g++){
for(int h = 0; h < boxWidth; h++){
...
声明循环变量时：
int g, h; //index for use in for loop
for(int g = 0; g < boxLength; g++){
for(int h = 0; h < boxWidth; h++){
...
（你可以选择任何你喜欢的名字）
除非您在独立环境（没有操作系统）中工作，否则您对void main（）
的声明是错误的。在符合标准的实现中，main
for的允许声明是int main（void）
和int main（int argc，char*argv[]）
（您将看到它是用等效的char**argv
编写的）。请参阅：
参数int argc和char**argv
允许您在命令行上将信息传递到程序中。不要硬编码文件名。（如果您在嵌入式系统上，这是一个例外，因为您可能无法在命令行上传递文件名），否则，您可以执行以下操作：
int main (int argc, char **argv)
{
int nptrs = WRDSZ, index, wordQuantity = 0; /* declare/initialize vars */
char box[BXLEN][BXWDT] = {{0}},
**words = NULL,
wordBankArray[ARRSZ] = "";
FILE *fp = NULL;
if (argc < 2 ) { /* validate 1 argument given for filename */
fprintf (stderr, "error: insufficient input,\n"
"usage: %s filename\n", argv[0]);
return 1;
}
/* open file/validate file open for reading */
if ((fp = fopen (argv[1], "r")) == NULL) {
perror ("fopen-argv[1]");
return 1;
}
for (int i = 0; i < wordQuantity; i++) /* free allocated strings */
free (words[i]);
free (words); /* free pointers */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <time.h>
#define BXLEN 20 /* if you need a constant, #define one (or more) */
#define BXWDT 75
#define WRDSZ 100
#define ARRSZ 1050
int main (int argc, char **argv)
{
int nptrs = WRDSZ, index, wordQuantity = 0; /* declare/initialize vars */
char box[BXLEN][BXWDT] = {{0}},
**words = NULL,
wordBankArray[ARRSZ] = "";
FILE *fp = NULL;
if (argc < 2 ) { /* validate 1 argument given for filename */
fprintf (stderr, "error: insufficient input,\n"
"usage: %s filename\n", argv[0]);
return 1;
}
for (int g = 0; g < BXLEN; g++) { /* initialize box */
for (int h = 0; h < BXWDT; h++) {
if (g == 0 || g == BXLEN - 1)
box[g][h] = '-';
else if (h == 0 || h == BXWDT - 1)
box[g][h] = '|';
else
box[g][h] = ' ';
}
}
/* open file/validate file open for reading */
if ((fp = fopen (argv[1], "r")) == NULL) {
perror ("fopen-argv[1]");
return 1;
}
srand (time (NULL)); /* seed rand generator */
if (!(words = malloc (nptrs * sizeof *words))) { /* allocate/validate */
perror ("malloc-words");
return 1;
}
while (fgets (wordBankArray, ARRSZ, fp) != NULL) { /* read each line in file */
size_t len; /* save length, then memcpy */
if (wordQuantity == nptrs) { /* check if all pointers used - realloc */
/* always realloc using a temporary pointer -- not the pointer itself */
void *tmp = realloc (words, 2 * nptrs * sizeof *words);
if (!tmp) { /* validate realloc succeeds */
perror ("realloc-words");
break; /* don't exit, original words pointer still valid */
}
words = tmp; /* assign reallocated block to original pointer */
nptrs *= 2; /* update number of pointers allocated */
}
if (!(words[wordQuantity] = malloc ((len = strlen (wordBankArray)) + 1))) {
perror ("malloc-words[wordQuantity]");
return 1;
}
memcpy (words[wordQuantity], wordBankArray, len + 1);
wordQuantity++;
}
fclose (fp);
fputs ("Randomly generated string from list : ", stdout);
index = rand() % wordQuantity;
printf ("%s\n", words[index]);
for (int g = 0; g < BXLEN; g++) {
for (int h = 0; h < BXWDT; h++) {
printf ("%c", box[g][h]);
}
putchar ('\n');
}
for (int i = 0; i < wordQuantity; i++) /* free allocated strings */
free (words[i]);
free (words); /* free pointers */
}
（注意：您必须验证每个分配）
请注意，您仅分配初始WRDSZ
（100
）指针。如果您的文件有1000个字，则必须跟踪已填充的指针数，（您的wordQuantity
），并且必须跟踪分配的指针数（例如使用nptrs
）。当wordQuantity==nptrs
时，您必须realloc
在尝试使用另一个指针之前，通过words
可用的指针数量（通常将当前分配的数量加倍是一个合理的增长方案）。添加额外的测试和重新分配，您的读取循环将变为：
while (fgets (wordBankArray, ARRSZ, fp) != NULL) { /* read each line in file */
size_t len; /* save length, then memcpy */
if (wordQuantity == nptrs) { /* check if all pointers used - realloc */
/* always realloc using a temporary pointer -- not the pointer itself */
void *tmp = realloc (words, 2 * nptrs * sizeof *words);
if (!tmp) { /* validate realloc succeeds */
perror ("realloc-words");
break; /* don't exit, original words pointer still valid */
}
words = tmp; /* assign reallocated block to original pointer */
nptrs *= 2; /* update number of pointers allocated */
}
if (!(words[wordQuantity] = malloc ((len = strlen (wordBankArray)) + 1))) {
perror ("malloc-words[wordQuantity]");
return 1;
}
memcpy (words[wordQuantity], wordBankArray, len + 1);
wordQuantity++;
}
fclose (fp);
（注意：您只需调用strlen（）
一次，保存大小，然后使用memcpy（）
复制字符串。如果调用strcpy（）
，您只需再次扫描调用strlen（）
中已有的字符串结尾）
阅读完毕后，在该点调用fclose（）
。还要注意sizeof（char）
是1
，应该从大小乘法中省略。剩下的部分将打印框并输出一个随机字符串，但请注意，如果输出中不需要转换，则无需调用printf
put
或fputs
即可（一个好的编译器会在幕后为您进行更改）
您错过的是释放已分配的内存。为此，您可以执行以下操作：
int main (int argc, char **argv)
{
int nptrs = WRDSZ, index, wordQuantity = 0; /* declare/initialize vars */
char box[BXLEN][BXWDT] = {{0}},
**words = NULL,
wordBankArray[ARRSZ] = "";
FILE *fp = NULL;
if (argc < 2 ) { /* validate 1 argument given for filename */
fprintf (stderr, "error: insufficient input,\n"
"usage: %s filename\n", argv[0]);
return 1;
}
/* open file/validate file open for reading */
if ((fp = fopen (argv[1], "r")) == NULL) {
perror ("fopen-argv[1]");
return 1;
}
for (int i = 0; i < wordQuantity; i++) /* free allocated strings */
free (words[i]);
free (words); /* free pointers */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <time.h>
#define BXLEN 20 /* if you need a constant, #define one (or more) */
#define BXWDT 75
#define WRDSZ 100
#define ARRSZ 1050
int main (int argc, char **argv)
{
int nptrs = WRDSZ, index, wordQuantity = 0; /* declare/initialize vars */
char box[BXLEN][BXWDT] = {{0}},
**words = NULL,
wordBankArray[ARRSZ] = "";
FILE *fp = NULL;
if (argc < 2 ) { /* validate 1 argument given for filename */
fprintf (stderr, "error: insufficient input,\n"
"usage: %s filename\n", argv[0]);
return 1;
}
for (int g = 0; g < BXLEN; g++) { /* initialize box */
for (int h = 0; h < BXWDT; h++) {
if (g == 0 || g == BXLEN - 1)
box[g][h] = '-';
else if (h == 0 || h == BXWDT - 1)
box[g][h] = '|';
else
box[g][h] = ' ';
}
}
/* open file/validate file open for reading */
if ((fp = fopen (argv[1], "r")) == NULL) {
perror ("fopen-argv[1]");
return 1;
}
srand (time (NULL)); /* seed rand generator */
if (!(words = malloc (nptrs * sizeof *words))) { /* allocate/validate */
perror ("malloc-words");
return 1;
}
while (fgets (wordBankArray, ARRSZ, fp) != NULL) { /* read each line in file */
size_t len; /* save length, then memcpy */
if (wordQuantity == nptrs) { /* check if all pointers used - realloc */
/* always realloc using a temporary pointer -- not the pointer itself */
void *tmp = realloc (words, 2 * nptrs * sizeof *words);
if (!tmp) { /* validate realloc succeeds */
perror ("realloc-words");
break; /* don't exit, original words pointer still valid */
}
words = tmp; /* assign reallocated block to original pointer */
nptrs *= 2; /* update number of pointers allocated */
}
if (!(words[wordQuantity] = malloc ((len = strlen (wordBankArray)) + 1))) {
perror ("malloc-words[wordQuantity]");
return 1;
}
memcpy (words[wordQuantity], wordBankArray, len + 1);
wordQuantity++;
}
fclose (fp);
fputs ("Randomly generated string from list : ", stdout);
index = rand() % wordQuantity;
printf ("%s\n", words[index]);
for (int g = 0; g < BXLEN; g++) {
for (int h = 0; h < BXWDT; h++) {
printf ("%c", box[g][h]);
}
putchar ('\n');
}
for (int i = 0; i < wordQuantity; i++) /* free allocated strings */
free (words[i]);
free (words); /* free pointers */
}
内存使用/错误检查
在您编写的任何动态分配内存的代码中，对于任何块，您都有两个职责