Question

How to check if second string a rotated version of first string in C

Answer 1

#include <stdio.h>
#include <stdbool.h>
#include <string.h>

bool isSecondStringRotatedOfFirstString(const char* first, const char* second) {
    int size_first = strlen(first);
    int size_second = strlen(second);
    
    if (size_first != size_second) {
        return false;
    }
    
    for (int i = 0; i < size_first; i++) {
        char rotated[256];
        strcpy(rotated, first + i);
        strncat(rotated, first, i);
        
        if (strcmp(rotated, second) == 0) {
            return true;
        }
    }
    
    return false;
}

int main() {
    const char* first = "abcdefg";
    const char* second = "cdefgab";
    
    printf("%s\n", isSecondStringRotatedOfFirstString(first, second) ? "yes" : "no");
    
    return 0;
}


 
 
 
/*
run:

yes
 
*/

 

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Answer 2

#include <stdio.h>
#include <stdbool.h>
#include <string.h>

bool isSecondStringRotatedOfFirstString(const char* first, const char* second) {
    if (strlen(first) != strlen(second)) {
        return false;
    }
    
    char concatenated[256];
    
    strcpy(concatenated, first);
    strcat(concatenated, first);
    
    return strstr(concatenated, second) != NULL;
}

int main() {
    const char* first = "abcdefg";
    const char* second = "cdefgab";
    
    printf("%s\n", isSecondStringRotatedOfFirstString(first, second) ? "yes" : "no");
    
    return 0;
}


 
 
/*
run:

yes
 
*/

 

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