Left-hand string

Description:

In assembly language, there is a shift instruction called ROL. Now a simple task is to simulate the operation result of this instruction using strings. For a given Character Sequence S, please shift its loop left K-bit sequence output. For example, the Character Sequence S = "abcxyzdef" requires that the output result of the loop be shifted three places left, that is, "xyzdefabc ". Is it easy? OK, get it done!

Input:

Multiple groups of test data. Each test data contains a Character Sequence s and a non-negative integer k. The length of S cannot exceed 1000.

Output:

Output a new sequence for each test case.

Sample input:

UDBOJ 4abba 1

Sample output:

JUDBObbaa

Ideas:

Similar to the order of flipped words:

1. First flip the first n characters;

2. After turning it over, len-n characters are returned;

3. Rotate it as a whole.

/* Left-hand string by rowandjj2014/8/16 */# include <stdio. h> # include <string. h> # include <stdlib. h> void reverse (char * pbegin, char * pend) {If (pbegin = NULL | pend = NULL) {return;} Char temp; while (pbegin <pend) {temp = * pbegin; * pbegin = * pend; * pend = temp; pbegin ++; pend --;}} // The number of left-handed characters whose pdata is the string n void leftrotatestring (char * pdata, int N) {If (pdata = NULL | n <= 0) {return ;} int Len = strlen (pdata); If (LEN <= 0) {return;} n = N % Len; // rotate the first n characters of reverse (pdata, pdata + N-1); // rotate the following len-n characters of reverse (pdata + N, pdata + len-1); // The overall rotation reverse (pdata, pdata + len-1);} int main () {char STR [1000]; int N; while (scanf ("% S % d", STR, & N )! = EOF) {leftrotatestring (STR, n); printf ("% s \ n", STR) ;}return 0 ;}