How to write a palindrome number algorithm in the C lan…

A common algorithm in C language to check if a number is a palindrome is by converting the number into a string and checking if the string is a palindrome. Here is an example code:

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

int isPalindrome(int num) {
    char str[20];
    sprintf(str, "%d", num); // 将整数转换为字符串

    int len = strlen(str);
    for (int i = 0; i < len/2; i++) {
        if (str[i] != str[len-i-1]) {
            return 0; // 不是回文数
        }
    }
    return 1; // 是回文数
}

int main() {
    int num;
    printf("请输入一个整数：");
    scanf("%d", &num);

    if (isPalindrome(num)) {
        printf("%d是回文数\n", num);
    } else {
        printf("%d不是回文数\n", num);
    }

    return 0;
}

In the code above, integers are converted to strings using the sprintf function. Then, a loop is used to traverse the first half of the string to check if it matches the corresponding second half. If any characters do not match, the number is not a palindrome. If no mismatches are found after the loop ends, then the number is a palindrome.