/**

* @author: wenlong.cao

* @file: Define a left shift string function. The time compleity should O(n) and

* Space complexity should be O(1)

* @date: 2016-10-31

*/

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <assert.h>

typedef void(*tpf)(char[],const int, int);

void left_shift_onebit(char* s, const int n)

{

char t = s[0];

for(int i = 1; i < n; ++i)

{

s[i - 1] = s[i];

}

s[n-1] = t;

}

void left_shift_method_1(char* s, const int n, int m)

{

while(m--)

{

left_shift_onebit(s, n);

}

}

void test_left_shift(tpf func)

{

char a[] = "abcdfg";

int size = strlen(a);

tpf f = func;

f(a, size, 2);

assert(strcmp(a, "cdfgab") == 0);

}

int main(int argc, char const *argv[])

{

test_left_shift(left_shift_method_1);

return 0;

}