hi,
I need some help on the following issue.
how should I declare a C/C++ function to return
"char *temp[] "
I tried to use char **, unfortunately it does not work.
basically, I want to achieve this. suppose temp = {"abc", "de","2"}
I want a function to be able to return a pointer so that I could
achieve "abc", "de", "2" one by one.
thanks
as you can see when you debug, Temp has every thing.
but test_output is unable to do the job, I can only call this
function once.
thanks for the help
#include <iostream.h>
#include <string.h>
const int LIST_LENGTH = 10;
const int STRING_LENGTH = 100;
char CHAR_ARRAY[STRING_LENGTH];
char *Temp[LIST_LENGTH];
char ** OutStr (char * In_Str, char delim);
int ParsePairs(char * str, char Left_Char, char Right_Char);
//return strlength if successful, 0 otherwise
int Parse(char *str, char delim); //normal strings
void main()
{
char *Test_Str = "\"asf,def\",<a,2>,3,{4,5}";
char **test_output;
test_output = OutStr(Test_Str, ',');
cout << "done\n";
return;
}
char **OutStr (char * In_Str, char delim)
{
//char *Temp[LIST_LENGTH];
char In_Str_Copy[STRING_LENGTH];
char Temp_Str[STRING_LENGTH];
char * Str_Ptr;
int i, j;
//first make a copy of the ctring
strcpy(In_Str_Copy, In_Str);
//strcpy(Temp_Str, In_Str);
Str_Ptr = In_Str_Copy;
//allocate memory
for (i=0; i<LIST_LENGTH; i++)
{
Temp[i] = new char[STRING_LENGTH];
Temp[i][0] = 0;
}
//parsing string
// null string
if(!In_Str)
return 0;
// string without delimiters
if(!strchr(In_Str_Copy, delim))
{
strcpy(Temp[0], In_Str_Copy);
return Temp;
}
j = 0;
int Normal_Flag = 0;
while(1) //process string
{
switch (In_Str_Copy[0])
{
case '(':
i = ParsePairs(In_Str_Copy, '(',')');
break;
case '<':
i = ParsePairs(In_Str_Copy, '<','>');
break;
case '{':
i = ParsePairs(In_Str_Copy, '{','}');
break;
case '[':
i = ParsePairs(In_Str_Copy, '[',']');
break;
case '"':
i = ParsePairs(In_Str_Copy, '"','"');
break;
default:
i = Parse(In_Str_Copy, delim);
Normal_Flag = 1;
}
//check In_Str_Copy[i], should be delim
//to be added
if(!Normal_Flag)
strncpy(Temp[j], In_Str_Copy, i+1);
else
strncpy(Temp[j], In_Str_Copy, i);
Normal_Flag = 0;
j++;
//check if this is the last character
i++;
//check delim
if(!In_Str_Copy[i])
return Temp;
if(In_Str_Copy[i] == delim)
{
i++;
}
if(In_Str_Copy[i])
{
strcpy(Temp_Str, Str_Ptr + i);
strcpy(In_Str_Copy, Temp_Str);
Str_Ptr = In_Str_Copy;
}
else
break;
}
return Temp;
}
int Parse(char *str, char delim)
{
int i = 0 ;
while (str[i] && (str[i] != delim))
i++;
return i;
}
int ParsePairs(char * str, char Left_Char, char Right_Char) //parse strings within pairs
{
if(str[0] != Left_Char)
return -1;
// search right_char
if(!strchr(str, Right_Char))
return -1;
int i = 1;
while(str[i] != Right_Char)
i++;
//str[i] = 0;
return i;
}
Just create a class that carries that info in a variable, and then return a variable of that type. I don't know if this is exactly what you want, but here's an example:
Code:#include<iostream.h> #include<conio.h> #include<string.h> class str { char temp[1024]; int len; public: str(char a[]="") { strcpy(temp,a); len=strlen(temp); } str operator+(str s1) { char b[1024]; strcpy(b,temp); b[len]='\0'; strcat(b,s1); str retval(b); return retval; } operator char*() { char retval[1024]; strcpy(retval,temp); retval[len]='\0'; return retval; } void display() { cout<<temp; } void addspace() { temp[len]=' '; len++; temp[len]='\0'; } int operator==(str s1); char* strreverse(); }; char* str::strreverse() { char n[1024]; int cpos=len-1; int npos=0; for( ; cpos>=0 ; cpos--) { n[npos]=temp[cpos]; npos++; } n[npos]='\0'; str retval(n); return retval; } int str::operator==(str s1) { int eq=0; int slen=strlen(s1); if (len>slen) { int t=0; t=slen; slen=len; len=t; } if (len==slen) { eq=1; slen--; for ( ; slen>=0 ; slen--) { if (s1[slen]!=temp[slen]) { eq=0; break; } } } return eq; }
"If you tell the truth, you don't have to remember anything"
-Mark Twain
Probably the easiest way is just to pass the array as a parameter as the code below shows. If you want it as the return instead, you need to make it a **char and dynamically allocate both dimensions. I can post how to do that also. I also changed you strncpy()'s to strncat()'s. Seems to work better on my computer. Also, I freed up the memory in main().
#include <iostream.h>
#include <string.h>
const int LIST_LENGTH = 10;
const int STRING_LENGTH = 100;
char CHAR_ARRAY[STRING_LENGTH];
void OutStr(char * In_Str, char delim, char *Temp[]);
int ParsePairs(char * str, char Left_Char, char Right_Char);
//return strlength if successful, 0 otherwise
int Parse(char *str, char delim); //normal strings
int main()
{
char *Test_Str = "\"asf,def\",<a,2>,3,{4,5}";
char *test_output[LIST_LENGTH];
OutStr(Test_Str, ',', test_output);
cout << test_output[0] << endl;
cout << test_output[1] << endl;
cout << test_output[2] << endl;
cout << test_output[3] << endl;
cout << test_output[4] << endl;
cout << "done\n";
for (int i=0; i<LIST_LENGTH; i++)
{
delete []test_output[i];
}
return 0;
}
void OutStr(char * In_Str, char delim, char *Temp[])
{
char In_Str_Copy[STRING_LENGTH];
char Temp_Str[STRING_LENGTH];
char * Str_Ptr;
int i, j;
//first make a copy of the ctring
strcpy(In_Str_Copy, In_Str);
//strcpy(Temp_Str, In_Str);
Str_Ptr = In_Str_Copy;
//allocate memory
for (i=0; i<LIST_LENGTH; i++)
{
Temp[i] = new char[STRING_LENGTH];
Temp[i][0] = 0;
}
//parsing string
// null string
if(!In_Str)
return;
// string without delimiters
if(!strchr(In_Str_Copy, delim))
{
strcpy(Temp[0], In_Str_Copy);
return;
}
j = 0;
int Normal_Flag = 0;
while(1) //process string
{
switch (In_Str_Copy[0])
{
case '(':
i = ParsePairs(In_Str_Copy, '(',')');
break;
case '<':
i = ParsePairs(In_Str_Copy, '<','>');
break;
case '{':
i = ParsePairs(In_Str_Copy, '{','}');
break;
case '[':
i = ParsePairs(In_Str_Copy, '[',']');
break;
case '"':
i = ParsePairs(In_Str_Copy, '"','"');
break;
default:
i = Parse(In_Str_Copy, delim);
Normal_Flag = 1;
}
//check In_Str_Copy[i], should be delim
//to be added
//strcpy(Temp[j],"");
if(!Normal_Flag)
//strncpy(Temp[j], In_Str_Copy, i+1);
strncat(Temp[j], In_Str_Copy, i+1);
else
//strncpy(Temp[j], In_Str_Copy, i);
strncat(Temp[j], In_Str_Copy, i);
Normal_Flag = 0;
j++;
//check if this is the last character
i++;
//check delim
if(!In_Str_Copy[i])
return;
if(In_Str_Copy[i] == delim)
{
i++;
}
if(In_Str_Copy[i])
{
strcpy(Temp_Str, Str_Ptr + i);
strcpy(In_Str_Copy, Temp_Str);
Str_Ptr = In_Str_Copy;
}
else
break;
}
return;
}
