我在C中为我的作业编写了一个程序，该程序应该采用文本并通过LED将其转换为摩尔斯电码。要知道我已经用LED替换了预定的闪烁长度：“这是一个__”。这是现在的工作，我会得到充分的信任，但我的问题是，是否有更好的方法来做到这一点？我知道必须有，而不是使用所有那些“如果”的陈述。但我是C的初学者。（这个代码的唯一缺点是它很长，你不能进入空格。）它目前的工作方式是它接受一个字符串并将其分成单个字母，然后在'for'中循环检查这些单独的字母以查找相应的摩尔斯电码。让我知道你的想法。
// MorseCode_Attempt1.cpp : Defines the entry point for the console application.
//
include<stdio.h>
include<conio.h>
include<string.h>
void main() {
char str[500];
printf("Enter a string you want in Morse Code with underscores as spaces: ");
scanf("%s", &str);
int i;
int stringLength = strlen(str);
for (i = 0; i < stringLength; i++) {
printf("\n[%c]\n", str[i]);
if (str[i] == 'a') {
printf("\nIt is an a.\n");
}
if (str[i] == 'b') {
printf("\nIt is an b.\n");
}
if (str[i] == 'c') {
printf("\nIt is an e.\n");
}
if (str[i] == 'd') {
printf("\nIt is an d.\n");
}
if (str[i] == 'e') {
printf("\nIt is an e.\n");
}
if (str[i] == 'f') {
printf("\nIt is an f.\n");
}
if (str[i] == 'g') {
printf("\nIt is an g.\n");
}
if (str[i] == 'h') {
printf("\nIt is an h.\n");
}
if (str[i] == 'i') {
printf("\nIt is an i.\n");
}
if (str[i] == 'j') {
printf("\nIt is an j.\n");
}
if (str[i] == 'k') {
printf("\nIt is an k.\n");
}
if (str[i] == 'l') {
printf("\nIt is an l.\n");
}
if (str[i] == 'm') {
printf("\nIt is an m.\n");
}
if (str[i] == 'n') {
printf("\nIt is an n.\n");
}
if (str[i] == 'o') {
printf("\nIt is an o.\n");
}
if (str[i] == 'p') {
printf("\nIt is an p.\n");
}
if (str[i] == 'q') {
printf("\nIt is an q.\n");
}
if (str[i] == 'r') {
printf("\nIt is an r.\n");
}
if (str[i] == 's') {
printf("\nIt is an s.\n");
}
if (str[i] == 't') {
printf("\nIt is an t.\n");
}
if (str[i] == 'u') {
printf("\nIt is an u.\n");
}
if (str[i] == 'v') {
printf("\nIt is an v.\n");
}
if (str[i] == 'w') {
printf("\nIt is an w.\n");
}
if (str[i] == 'x') {
printf("\nIt is an x.\n");
}
if (str[i] == 'y') {
printf("\nIt is an y.\n");
}
if (str[i] == 'z') {
printf("\nIt is an z.\n");
}
if (str[i] == '_') {
printf("\nIt is a SPACE.\n");
}
}
return 0;
}
答案 0 :(得分：2)
当您使用大量if's并且在一场比赛后，您必须继续前进，然后使用if-else-if ladder，这样如果说＆＃39; b＆＃39;找到然后它不会检查所有其他条件。
但这里最好的解决方案是switch case。
在for-loop中尝试这样的事情。
switch (str[i])
{
case 'a':
printf("\nIt is an a.\n");
break;
case 'b':
printf("\nIt is a b.\n");
break;
/* etc. etc. etc.*/
default:
//default will work when the input to the switch->here str[i] does not match any case.
printf("\nNot a character or space!");
break;
}
答案 1 :(得分：1)
试试这个：
for (...)
{
char c = str[i];
unsigned Num;
/* If c is a letter map it to 0..25 */
Num = (unsigned)(toupper(c)-'A');
if (Num<26) //This matches only with letters, as Num is unsigned.
{
//Each letter is represented by max four symbols
static const char MorseCodes[26][5]=
{
"._", //Morsecode for 'a'
"_...", //Morsecode for 'b'
...
"__..", //Morsecode for 'z'
};
printf("You have entered the letter %c. The morse code is %s\n", Num+'A', MorseCodes[Num]);
}
else
if (c=='_')
{
printf ("Space\n");
}
else
{
printf ("What You Are Doing?\n");
}
}
答案 2 :(得分：0)
根据您的问题，以下代码应引导您朝着正确的方向前进。
请注意，函数：out（），函数：delay（），＃define ON和#define OFF取决于您的环境。
include<stdio.h>
//include<conio.h> -- dont include header files that are not used
include<string.h>
// adjust DELAY_UNIT as necessary
#define DELAY_UNIT (1000)
#define DOT_TIME (1)
#define DASH_TIME (3)
#define INTER_WORD_TIME (7)
#define INTER_CHAR_TIME (3)
#define DOT ('.')
#define DASH ('-')
// OP needs to define function 'out()', LED, ON, OFF and DELAY_UNIT
// to suit the environment
// prototypes
char *findIndex( struct morseStruct *morse, char ch);
void MorseToLed( char *sequencePtr);
void delay( long unsigned int );
/*
* If the duration of a dot is taken to be one unit
* then that of a dash is three units.
*
* The space between the components of one character is one unit,
*
* between characters is three units and between words seven units.
*
* To indicate that a mistake has been made and for the receiver to delete the last word,
* send ........ (eight dots).
*/
// see <http://morsecode.scphillips.com/morse2.html> for source list
// of morse code char formats
struct morseStruct
{
char searchChar;
char *morseSequence;
};
static const struct morseStruct *alphanumeric[] =
{
{'A', ",-" };
{'B', "-..." };
{'C', "-.-." };
... // add other alphameric definitions here
{0, NULL};
};
static const struct morseStruct *punctuation[] =
{
{'.', ".-.-.-" }; // period
{',', "--..--" }; // comma
{':', "---..." }; // colon
{'?', "..--.." }; // question mark
{'\'', ".----."}; // apostrophe (note: must escape certain characters)
{'-', "-....-" }; // hyphen
{'/', "-..-." }; // right slash
{'\"', ".-..-."}; // quotation mark
{'@', ".--.-." }; // at sign
{'=', "-...-" }; // equals sign
{0, NULL};
};
static const struct morseStruct *prosigns[] =
{
... // add prosigns here
{0, NULL};
};
int main( void )
{
char str[500];
printf("Enter a string you want in Morse Code with underscores as spaces: ");
if( NULL == fgets(str, sizeof( str ), stdin );
{ // then fgets failed
perror( "fgets for user input string failed");
exit( EXIT_FAILURE );
}
// implied else, fgets successful
//eliminate trailing newline, if any
if( char *pNewline = strstr( str, "\n")
{
pNewline = '\n';
}
size_t stringLength = strlen(str);
int i;
for (i = 0; i < stringLength; i++)
{
printf("\n[%c]\n", str[i]);
// handle special cases
if '_' == str[i] )
{ // then between words
//out(LED, OFF); // should already be OFF
delay( INTER_WORD_TIME*DELAY_UNIT );
continue;
}
int sequencePtr;
if( NULL == (sequencePtr = findIndex( alphaNumeric, str[i] ) ) )
{// then not alphanumeric value
if( NULL == (sequencePtr = findIndex( punctuation, str[i] ) ) )
{ // then not punctuation value
if( NULL == (sequencePtr = findIndex( prosigns, str[i] ) ) )
{ // then not prosign value
printf( "char: %0X is not recognized\n", str[i]);
continue;
}
}
}
MorseToLed (sequencePtr);
} // end for
return 0;
} // end function: main
char *findIndex( struct morseStruct *morse, char ch)
{
char *pSequence = NULL;
int i = 0;
while( NULL != morse[i].morseSequence )
{
if( ch == morse[i].searchChar )
{ // then found desire morse code sequence
pSequence = morse[i].morseSequence;
break;
}
i++;
}
return( pSequence );
} // end function: findIndex
void MorseToLed( char *sequencePtr)
{
size_t i = strlen( sequencePtr );
for( size_t j = 0; j<i; j++)
{
if( DOT == sequencePtr[j] )
{
out(LED, ON);
delay( DOT_TIME * DELAY_UNIT );
out(LED, OFF);
}
else if( DASH == sequencePtr[j] )
{
out(LED, ON);
delay( DASH_TIME * DELAY_UNIT );
out(LED, OFF);
}
delay( DELAY_UNIT ); // delay between components of one char
} // end for
delay( INTER_CHAR_TIME * DELAY_UNIT ); // delay between characters
} // end function: MorseToLed
void delay( long unsigned int delayUnits )
{
?????
} // end function: delay