[C언어 #29] 문자열 비교

C언어 문자열 비교

1. Compare strings

2. strcmp()

 

 

strcmp 없이 - Compare strings

/* Compare strings */
#include <stdio.h>
#include <string.h>
 
// Compare two strings
// Return -1 or 0 or 1
int compare(char str1[], char str2[]) {
    int i;
    for (i = 0; str1[i] != '\0'; i++)
        if (str1[i] != str2[i]) break;        
    int compare = str1[i] - str2[i];
 
    if (compare == 0) compare = 0;
    else if (compare < 0) compare = -1;
    else compare = 1;
 
    return compare;
}
 
// Test compare method
void testCompare() {
    printf("compare v. strcmp\n");
    printf("%6d  v. %2d\n", compare("xy", "xyz"), strcmp("xy", "xyz"));
    printf("%6d  v. %2d\n", compare("xyz", "xy"), strcmp("xyz", "xy"));
    printf("%6d  v. %2d\n", compare("", "a"), strcmp("", "a"));
    printf("%6d  v. %2d\n", compare("a", ""), strcmp("a", ""));
    printf("%6d  v. %2d\n", compare("", ""), strcmp("", ""));  
    printf("%6d  v. %2d\n", compare("apple", "orange"), strcmp("apple", "orange"));
    printf("%6d  v. %2d\n", compare("orange", "apple"), strcmp("orange", "apple"));
    printf("%6d  v. %2d\n", compare("apple", "apple"), strcmp("apple", "apple"));
}
 
int main() {
    testCompare();
 
    char str1[] = "xy";
    char str2[] = "xy";
    printf("%s & %s: %d\n", str1, str2, compare(str1, str2));
}

 

 

 

 

strcmp()

/* Compare strings */
#include <stdio.h>
#include <string.h>
 
int main() {
    char str1[] = "xy";
    char str2[] = "xy";
    if (strcmp(str1, str2) == 0) printf("Same\n");
    else printf("Different\n");
}

 

 

 

/* Compare strings */
#include <stdio.h>
#include <string.h>
 
int strCompare(char str1[], char str2[]) {
    return strcmp(str1, str2);
}
 
void print(int strcmp) {
    if (strcmp == 0) printf("Same\n");
    else printf("Different\n");
}
 
int main() {
    char str1[] = "xy";
    char str2[] = "xy";
    print(strCompare(str1, str2));
}