Interview Preparation Strings

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 = len1/2; 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(*str) { if( *(str+j) == ' ' || *(str+j) == '\0') { reverse( str+i, j-i ); i = j+1; } if( *(str+j) == '\0') { break; } j++; } /* * 2nd Step */ reverse(str,strlen(str)); }

Find the last word in a string

TODO