I found this code below on the internet which is suppose to count the sentences on an 8051 MCU.
Can someone please explain to me what is exactly happening where there are question marks.
Any kind of help would be highly appreciated.
#include<string.h>
char code *text=" what is a program? that has, a a lot of errors! When " ;
char code *text1=" you compile. this file, uVision. reports a number of? ";
char code *text2=" problems that you! may interactively correct. " ; //Null characters are also included in array!!!
void count ( char pdata* , char pdata*);
void main (void){
char pdata Nw,Ns;
char data TextNw[2],TextNs[2];
count(&Nw, &Ns); // call subroutine
TextNw[0]=Nw/10; //?????????????????????????????????
TextNw[1]=Nw%10; //?????????????????????????????????
TextNs[0]=Ns/10; //?????????????????????????????????
TextNs[1]=Ns%10; //?????????????????????????????????
while(1);
}
void count ( char pdata *Nw, char pdata *Ns ){
unsigned char N, i, ch;
typedef enum {idle1, idle2} state; //?????????????????????????????????
state S; // begining state
P2=0x00; // pdata bank definition it must be performed first!!
*Ns=*Nw=0; // without proper start-up there is no initialisation, initialise now!!
S=idle1; // beginning state
N=strlen(text)+strlen(text1)+strlen(text2)+3; //????????????? + 3 to acount 3 Null characters!
P2=0x00; // pdata bank definition
for(i=0;i!=N;i++){
ch=text[i]; // take a caharacter from the text
switch (S)
{
case (idle1):{
if (ch==0) break; // skip NULL terminating character!
if (ch!=' '){
S=idle2;
(*Nw)++;
}
break;
}
case(idle2):{
if (ch==0) break; // skip NULL terminating character!
if((ch==' ')||(ch==','))S=idle1;
else if ((ch=='?')||(ch=='.')||(ch=='!')){
S=idle1;
(*Ns)++;
}
break;
}
}
}
}
This program does 2 things in conjunction - counts number of sentences in the text and counts the number of words in the text. Once the counting is done, the results are stored in 2-char arrays. For example, for 57 words in 3 sentences the results will be stored as this: TextNw = {'5','7'} and TextNs = {'0','3'}.
The variable N contains the full length of the text with the addition of 3 null terminating characters (one per sentence).
The algorithm simultaneously counts words and sentences. In idle1 state the counting is in word-counting mode. In idle2 state the counting is in sentence-counting mode. The modes are interchanged according to current character being read - if delimiter is encountered, the appropriate counter is increased.
Related
If the below code is compiled with UNICODE as compiler option, the GetComputerNameEx API returns junk characters.
Whereas if compiled without UNICODE option, the API returns truncated value of the hostname.
This issue is mostly seen with Asia-Pacific languages like Chinese, Japanese, Korean to name a few (i.e., non-English).
Can anyone throw some light on how this issue can be resolved.
# define INFO_SIZE 30
int main()
{
int ret;
TCHAR infoBuf[INFO_SIZE+1];
DWORD bufSize = (INFO_SIZE+1);
char *buf;
buf = (char *) malloc(INFO_SIZE+1);
if (!GetComputerNameEx((COMPUTER_NAME_FORMAT)1,
(LPTSTR)infoBuf, &bufSize))
{
printf("GetComputerNameEx failed (%d)\n", GetLastError());
return -1;
}
ret = wcstombs(buf, infoBuf, (INFO_SIZE+1));
buf[INFO_SIZE] = '\0';
return 0;
}
In the languages you mentioned, most characters are represented by more than one byte. This is because these languages have alphabets of much more than 256 characters. So you may need more than 30 bytes to encode 30 characters.
The usual pattern for calling a function like wcstombs goes like this: first get the amount of bytes required, then allocate a buffer, then convert the string.
(edit: that actually relies on a POSIX extension, which also got implemented on Windows)
size_t size = wcstombs(NULL, infoBuf, 0);
if (size == (size_t) -1) {
// some character can't be converted
}
char *buf = new char[size + 1];
size = wcstombs(buf, infoBuf, size + 1);
I have a problem in regards of extracting signed int from string in c++.
Assuming that i have a string of images1234, how can i extract the 1234 from the string without knowing the position of the last non numeric character in C++.
FYI, i have try stringstream as well as lexical_cast as suggested by others through the post but stringstream returns 0 while lexical_cast stopped working.
int main()
{
string virtuallive("Images1234");
//stringstream output(virtuallive.c_str());
//int i = stoi(virtuallive);
//stringstream output(virtuallive);
int i;
i = boost::lexical_cast<int>(virtuallive.c_str());
//output >> i;
cout << i << endl;
return 0;
}
How can i extract the 1234 from the string without knowing the position of the last non numeric character in C++?
You can't. But the position is not hard to find:
auto last_non_numeric = input.find_last_not_of("1234567890");
char* endp = &input[0];
if (last_non_numeric != std::string::npos)
endp += last_non_numeric + 1;
if (*endp) { /* FAILURE, no number on the end */ }
auto i = strtol(endp, &endp, 10);
if (*endp) {/* weird FAILURE, maybe the number was really HUGE and couldn't convert */}
Another possibility would be to put the string into a stringstream, then read the number from the stream (after imbuing the stream with a locale that classifies everything except digits as white space).
// First the desired facet:
struct digits_only: std::ctype<char> {
digits_only(): std::ctype<char>(get_table()) {}
static std::ctype_base::mask const* get_table() {
// everything is white-space:
static std::vector<std::ctype_base::mask>
rc(std::ctype<char>::table_size,std::ctype_base::space);
// except digits, which are digits
std::fill(&rc['0'], &rc['9'], std::ctype_base::digit);
// and '.', which we'll call punctuation:
rc['.'] = std::ctype_base::punct;
return &rc[0];
}
};
Then the code to read the data:
std::istringstream virtuallive("Images1234");
virtuallive.imbue(locale(locale(), new digits_only);
int number;
// Since we classify the letters as white space, the stream will ignore them.
// We can just read the number as if nothing else were there:
virtuallive >> number;
This technique is useful primarily when the stream contains a substantial amount of data, and you want all the data in that stream to be interpreted in the same way (e.g., only read numbers, regardless of what else it might contain).
Im trying to make a recursive menu.
This program will later work with a tree(hojanodo), thats why I keep track of the root.
Problem: For some reason the fgets/fgetc is being skipped inside the recursivity on the second run, why does this happen?
I want the user to input either 1,2 or 3.(int)
What would be the fix for this? and is this the best way to implement a menu?
Here's what I have right now:(It compiles and runs so you can test it out but doesn't really work like I would like to..)
#include<stdio.h>
#include<stdlib.h>
typedef struct node{
char ch;
int i;
struct node *left;
struct node *right;
}hojaNodo;
int handle_menu(int eventHandler, hojaNodo **root);
int opcion_menu();
char get_symbol();
int get_userMenuInput();
int intro();
int main(){
hojaNodo *treeRoot = NULL;
intro();
// system("clear");
handle_menu(opcion_menu(), &treeRoot);
return 0;
}
int opcion_menu(){
int userOption;
printf("1.Agrega un Simbolo.\n");
printf("2.Listar Codigo\n");
printf("3.Exit");
userOption = get_userMenuInput();
printf("User: %d",userOption);
if(userOption < 4 && userOption > 0){
return userOption;
}
else
return -1;
}//eof opcion_menu
int handle_menu(int userOption,hojaNodo **root){
hojaNodo *tempRoot = NULL;
tempRoot = *root;
int valor;
char simbol;
switch(userOption){
case 1:
simbol = get_symbol();
printf("Simbol: %c", simbol);
break;
case 2:
printf("List Nodes\n");
break;
case 3:
printf("Exit");
userOption = -1;
// destroy_tree(root);
break;
default:
printf("userOption Error, Bye!");
break;
}//eof switch
if(userOption != -1)
handle_menu(opcion_menu(),&tempRoot);
// return userOption;
return -1;
}//eof menu()
char get_symbol(){
/*char userKey[3]
fgets(userKey,len,stdin);*/
char simbolo;
printf("Give me a symbol.");
simbolo = fgetc(stdin);
return simbolo;
}
int get_userMenuInput(){
char userKey[3];
int userOption;
size_t len;
len = sizeof(userKey);
fgets(userKey,len,stdin);
userOption = atoi(userKey);
//printf("User Option: %d\n", userOption);
return userOption;
}
Well apart from all the comments related to recursion and other changes suggested, please check this out. fgets() function needs flushing the input stream. It can be done using fflush() or fgetc().
A simple solution would be:
In function:
int opcion_menu(){
...
fgets(userKey,2,stdin);
fgetc(stdin); // Add this statement
Also in function:
int handle_menu(int userOption,hojaNodo **root)
case 1:
printf("Give me a choice : ");
fgets(userKey,2,stdin);
fgetc(stdin); // add this statement
fgets reads in at most one less than size characters from stream and stores them into the buffer pointed to by string. This will lead the newline character still available in Input Stream which need to be flushed. If this newline character is not read from Input stream, than this would become the input for next fgets function and ultimately it will skip the fgets(since it has already got its input a newline character)
fgetc(stdin) will flush out these extra newline character.
I don't know if this might help anyone.
In my case, I had to 'free' the buffer from the char with this function:
void clean(){
char cTemp;
while((cTemp = getchar()) != '\n')
;
}
Im not really sure why this works but it does(if anyone does, please add it to my answer).
I call it right before I call get_userOption();
I am using a toolkit to do some Elliptical Curve Cryptography on an ATMega2560. When trying to use the print functions in the toolkit I am getting an empty string. I know the print functions work because the x86 version prints the variables without a problem. I am not experienced with ATMega and would love any help on this matter. The print code is included below.
Code to print a big number (it itself calls a util_print)
void bn_print(bn_t a) {
int i;
if (a->sign == BN_NEG) {
util_print("-");
}
if (a->used == 0) {
util_print("0\n");
} else {
#if WORD == 64
util_print("%lX", (unsigned long int)a->dp[a->used - 1]);
for (i = a->used - 2; i >= 0; i--) {
util_print("%.*lX", (int)(2 * (BN_DIGIT / 8)),
(unsigned long int)a->dp[i]);
}
#else
util_print("%llX", (unsigned long long int)a->dp[a->used - 1]);
for (i = a->used - 2; i >= 0; i--) {
util_print("%.*llX", (int)(2 * (BN_DIGIT / 8)),
(unsigned long long int)a->dp[i]);
}
#endif
util_print("\n");
}
}
The code to actually print a big number variable:
static char buffer[64 + 1];
void util_printf(char *format, ...) {
#ifndef QUIET
#if ARCH == AVR
char *pointer = &buffer[1];
va_list list;
va_start(list, format);
vsnprintf(pointer, 128, format, list);
buffer[0] = (unsigned char)2;
va_end(list);
#elif ARCH == MSP
va_list list;
va_start(list, format);
vprintf(format, list);
va_end(list);
#else
va_list list;
va_start(list, format);
vprintf(format, list);
fflush(stdout);
va_end(list);
#endif
#endif
}
edit: I do have UART initialized and can output printf statments to a console.
I'm one of the authors of the RELIC toolkit. The current util_printf() function is used to print inside the Avrora simulator, for debugging purposes. I'm glad that you could adapt the code to your purposes. As a side note, the buffer size problem was already fixed in more recent releases of the toolkit.
Let me know you have further problems with the library. You can either contact me personally or write directly to the discussion group.
Thank you!
vsnprintf store it's output on the given buffer (which in this case is the address point by pointer variable), in order for it to show on the console (through UART) you must send your buffer using printf (try to add printf("%s", pointer) after vsnprintf), if you're using avr-libc don't forget to initialized std stream first before making any call to printf function
oh btw your code is vulnerable to buffer overflow attack, buffer[64 + 1] means your buffer size is only 65 bytes, vsnprintf(pointer, 128, format, list); means that the maximum buffer defined by your application is 128 bytes, try to change it below 65 bytes in order to avoid overflow
Alright so I found a workaround to print the bn numbers to a stdout on an ATMega2560. The toolkit comes with a function that writes a variable to a string (bn_write_str). So I implemented my own print function as such:
void print_bn(bn_t a)
{
char print[BN_SIZE]; // max precision of a bn number
int bi = bn_bits(a); // get the number of bits of the number
bn_write_str(print, bi, a, 16) // 16 indicates the radix (hexadecimal)
printf("%s\n"), print);
}
This function will print a bn number in hexadecimal format.
Hope this helps anyone using the RELIC toolkit with an AVR.
This skips the util_print calls.
Why does the following code throw an exception when getting to the second scanf_s after entering an number to put into the struct.
This by no means represents a complete linked list implementation.
Not sure how to get onto the next scanf_s when having entered the value? Any ideas?
EDIT: Updated code with suggested solution, but still get an AccessViolationException after first scanf_s
Code:
struct node
{
char name[20];
int age;
float height;
node *nxt;
};
int FillInLinkedList(node* temp)
{
int result;
temp = new node;
printf("Please enter name of the person");
result = scanf_s("%s", temp->name);
printf("Please enter persons age");
result = scanf_s("%d", &temp->age); // Exception here...
printf("Please enter persons height");
result = scanf_s("%f", &temp->height);
temp->nxt = NULL;
if (result >0)
return 1;
else return 0;
}
// calling code
int main(array<System::String ^> ^args)
{
node temp;
FillInLinkedList(&temp);
...
You are using scanf_s with incorrect parameters. Take a look at the examples in the MSDN documentation for the function. It requires that you pass in the size of the buffer after the buffer for all string or character parameters. So
result = scanf_s("%s", temp->name);
should be:
result = scanf_s("%s", temp->name, 20);
The first call to scanf_s is reading garbage off the stack because it is looking for another parameter and possibly corrupting memory.
There is no compiler error because scanf_s uses a variable argument list - the function doesn't have a fixed number of parameters so the compiler has no idea what scanf_s is expecting.
You need
result = scanf_s("%d", &temp->age);
and
result = scanf_s("%f", &temp->height);
Reason is that sscanf (and friends) requires a pointer to the output variable so it can store the result there.
BTW, you have a similar problem with the parameter temp of your function. Since you're changing the pointer (and not just the contents of what it points to), you need to pass a double pointer so that the changes will be visible outside your function:
int FillInLinkedList(node** temp)
And then of course you'll have to make the necessary changes inside the function.
scanf() stores data into variables, so you need to pass the address of the variable (or its pointer)Example:
char string[10];
int n;
scanf("%s", string); //string actually points to address of
//first element of string array
scanf("%d", &n); // &n is the address of the variable 'n'
%19c should be %s
temp->age should be &temp-age
temp->height should be &temp->height
Your compiler should be warning you
about these errors
I believe you need to pass parameters to scanf() functions by address. i.e. &temp->age
otherwise temp-age will be interpreted as a pointer, which will most likely crash your program.