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Write a function that finds the last instance of a character in a string.
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(15 votes, avg: 3.13)
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Write a function that finds the last instance of a character in a string.
6,954 Views | (15 votes, avg: 3.13)
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#include <stdio.h>
main() {
char *x= “acbcd”;
char y = ‘c’;
int len = strlen(x);
int i=0,j=0;
for( i = len-1; i>= 0; i– ) {
if ( x[i] == y ) {
break;
}
}
printf(”%s%c%s%d%s”,”the # of last occur of “,y,” is “,i+1,”n”);
}
avdate your solution is to slow.
char *lastchar(char *pszStr,char chMatch)
{
char *pchrtn = NULL;
while( *pszStr++ != NULL )
if( *pszStr == chMatch ) pchrtn=pszStr;
return pchrtn;
}
too slow is avery dicey term. If its a very long string then it make a lot of good sense to start from the end.
in such a case your solution would be “too slow”
int lastinstance(char *s, char c)
{
int x=strlen(s);
for(; x>=0;x–)
{
if(s[x]==c)
return x+1;
}
return 0;
}
Doesn’t strlen() do a forward scan until it finds ‘ ’? If so, then calling strlen() and then starting from the end is actually slower than starting from the begining. Not much, but a little bit.
C functon
————-
- you have have this preprocessor
#include
char Last_Char(char *Str)
{
return Str[strlen(Str) -1] ;
}
C++
——
- you have have this preprocessor
#include
char Last_Char(string Str)
{
int final = Str.size() - 1 ;
retun Str.at (final);
}
Assumes psz is a NULL terminated string (if you have a length then use psz+cch and work backwards). Returns a pointer to the last character found.
char *PchLastChar(char *psz, char chToFind)
{
char *pchLast = NULL;
while (*psz)
{
if (*psz == chToFind)
pchLast = psz;
psz++;
}
return pchLast;
}
Here is the solution to this in C# (not using any string internal function such as indexOf, lastIndexOf)
private int GetLastInstanceIndex(string input, char c)
{
//decl
int count;
bool found;
//init
count = 0;
found = false;
if (input == “” || input==null)
return -1;
// get the string into an array of characters
char[] arrInput = input.ToCharArray();
for (count = arrInput.Length - 1; count >= 0; count–)
{
if (arrInput[count] == c)
{
found = true;
break;
}
}
if (found)
return count;
else
return -1;
}
#include
int substr(char *x,char y);
int main()
{
char *stringIn=”testing”;
int i;
i=substr(stringIn, ‘g’);
printf(”The Last Occurence of the alphabet is %d”, i);
}
int substr(char *x,char y){
int i=0;int j=0;
for( ;*x!=”;j++){
if(*x==y){i=j;}
x++;}
return i;}
This gives the relative position.
Scan both sides of string in a single for loop:
int lastIndexOf(char *phrase, char match)
{
int len = strlen(phrase);
char array[len];
int pos = -1;
//convert the dam thing to char array
for(int i = 0; i pos)
{
pos = i;
break;
}
}
if(array[i] == match)
{
pos = i;
}
if(array[len-i] == match)
{
pos = len-i;
}
}
return pos+1;
}
//if the characters are even
else
{
for(int i=0; i
C++
compiled by g++
#include
#include
#include
using namespace std;
bool IsAlpha( char x ) { return isalpha(x); };
main() {
string test = “abcdjk jfdjl jlsj !#@”;
cout
using namespace std;
bool IsAlpha( char x ) { return isalpha(x); };
string test = “abcdjk jfdjl jlsj !#@”
*find_if( test.rbegin(), test.rend(), IsAlpha );
void main()
{ char *p=”niskam”
while(*p)
{ p++; }
p–
printf(”%c”,*p);
getche();
}
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