C：strchr()和index()之间的区别

C语言中的strchr()和index()函数都用于在字符串中查找某个字符的位置。它们的功能类似，但有一些细微的区别。

char *strchr(const char *str, int c);

c
#include 
#include 
int main() {
    const char *str = "Hello, World!";
    char c = 'o';
    char *ptr = strchr(str, c);
    
    if (ptr != NULL) {
        printf("Found character '%c' at position %ld\n", c, ptr - str);
    } else {
        printf("Character '%c' not found\n", c);
    }
    
    return 0;
}

char *index(const char *str, int c);

c
#include 
#include 
int main() {
    const char *str = "Hello, World!";
    char c = 'o';
    char *ptr = index(str, c);
    
    if (ptr != NULL) {
        printf("Found character '%c' at position %ld\n", c, ptr - str);
    } else {
        printf("Character '%c' not found\n", c);
    }
    
    return 0;
}