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