Difference between revisions of "Interview Preparation Strings"
From Embedded Systems Learning Academy
Proj user14 (talk | contribs) (→Reverse words in a string) |
Proj user14 (talk | contribs) (→Reverse words in a string) |
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<BR/> | <BR/> | ||
== Reverse words in a string == | == Reverse words in a string == | ||
| − | |||
If string to be reversed is "where there is a will there is a way" | If string to be reversed is "where there is a will there is a way" | ||
Output needed : "way a is there will a is there where" | Output needed : "way a is there will a is there where" | ||
| − | |||
<BR/> | <BR/> | ||
To reverse the words in a string , we will follow below steps: | To reverse the words in a string , we will follow below steps: | ||
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<BR/> | <BR/> | ||
2) Second, we will reverse this string by letter to get the desired output. | 2) Second, we will reverse this string by letter to get the desired output. | ||
| − | < | + | <BR/> |
| − | BR/> | ||
We are going to use previous reverse_str function with one more parameter length as below: | We are going to use previous reverse_str function with one more parameter length as below: | ||
<syntaxhighlight lang="c"> | <syntaxhighlight lang="c"> | ||
| + | |||
void reverse_str(char *s ,int len) | void reverse_str(char *s ,int len) | ||
{ | { | ||
| − | + | int i,j; | |
char temp; | char temp; | ||
j= len - 1; | j= len - 1; | ||
| − | int mid = | + | int mid = len/2; |
for(i=0;i<mid;i++,j--) | for(i=0;i<mid;i++,j--) | ||
{ | { | ||
| Line 53: | Line 51: | ||
* In below while loop , string becomes "erehw ereht si a lliw ereht si a yaw" | * In below while loop , string becomes "erehw ereht si a lliw ereht si a yaw" | ||
*/ | */ | ||
| − | while(* | + | while(*s) |
{ | { | ||
| − | if( *( | + | if( *(s+j) == ' ' || *(s+j) == '\0') |
{ | { | ||
| − | reverse( | + | reverse( s+i, j-i ); |
i = j+1; | i = j+1; | ||
} | } | ||
| − | if( *( | + | if( *(s+j) == '\0') |
{ | { | ||
break; | break; | ||
| Line 69: | Line 67: | ||
* 2nd Step | * 2nd Step | ||
*/ | */ | ||
| − | reverse( | + | reverse(s,strlen(s)); |
} | } | ||
</syntaxhighlight> | </syntaxhighlight> | ||
Revision as of 21:32, 24 November 2016
Contents
Reverse a string
void reverse_str(char *s)
{
const int len = strlen(s);
const int mid = len / 2;
for (int i = 0, j=len-1; i < mid; i++, j--) {
char c = s[i];
s[i] = s[j];
s[j] = c;
}
}
Reverse words in a string
If string to be reversed is "where there is a will there is a way"
Output needed : "way a is there will a is there where"
To reverse the words in a string , we will follow below steps:
1) First, we will reverse each word in the string as "erehw ereht si a lliw ereht si a yaw"
2) Second, we will reverse this string by letter to get the desired output.
We are going to use previous reverse_str function with one more parameter length as below:
void reverse_str(char *s ,int len)
{
int i,j;
char temp;
j= len - 1;
int mid = len/2;
for(i=0;i<mid;i++,j--)
{
temp = s[i];
s[i] = s[j];
s[j] = temp;
}
}
void reverse_words_in_string(char *s)
{
int i=0;
int j=0;
/*
* 1st step
* In below while loop , string becomes "erehw ereht si a lliw ereht si a yaw"
*/
while(*s)
{
if( *(s+j) == ' ' || *(s+j) == '\0')
{
reverse( s+i, j-i );
i = j+1;
}
if( *(s+j) == '\0')
{
break;
}
j++;
}
/*
* 2nd Step
*/
reverse(s,strlen(s));
}
Find the last word in a string
TODO
