linux 字符串处理函数

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

int main() {
    char str[] = "Hello, World!";
    int len = strlen(str);
    printf("Length of string is %d\n", len);
    return 0;
}

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

int main() {
    char str1[] = "apple";
    char str2[] = "banana";
    int result = strcmp(str1, str2);
    if (result == 0) {
        printf("Strings are equal.\n");
    } else if (result < 0) {
        printf("str1 is less than str2.\n");
    } else {
        printf("str1 is greater than str2.\n");
    }
    return 0;
}

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

int main() {
    char str[] = "Hello, World!";
    char *pos = strstr(str, "World");
    if (pos != NULL) {
        printf("Found at position: %ld\n", pos - str);
    } else {
        printf("Not found.\n");
    }
    return 0;
}

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

void str_replace(char *str, const char *old_str, const char *new_str) {
    char buffer[1000];
    char *ch;
    char *search = str;
    while ((ch = strstr(search, old_str)) != NULL) {
        strncpy(buffer, search, ch - search);
        buffer[ch - search] = '\0';
        strcat(buffer, new_str);
        strcat(buffer, ch + strlen(old_str));
        strcpy(str, buffer);
        search = str + (ch - str) + strlen(new_str);
    }
}

int main() {
    char str[] = "Hello, World!";
    str_replace(str, "World", "Linux");
    printf("Modified string: %s\n", str);
    return 0;
}