请写出最长公共子串的c++代码

Sure, here is the C code for finding the longest common substring:

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

void findLCS(char* str1, char* str2) {
    int len1 = strlen(str1);
    int len2 = strlen(str2);
    
    int LCSuff[len1 + 1][len2 + 1];
    int result = 0;
    
    for (int i = 0; i <= len1; i++) {
        for (int j = 0; j <= len2; j++) {
            if (i == 0 || j == 0)
                LCSuff[i][j] = 0;
                
            else if (str1[i - 1] == str2[j - 1]) {
                LCSuff[i][j] = LCSuff[i - 1][j - 1] + 1;
                result = LCSuff[i][j] > result ? LCSuff[i][j] : result;
            }
            
            else
                LCSuff[i][j] = 0; 
        }
    }

    printf("The length of the longest common substring is %d", result);
}

int main() {
    char str1[] = "abcdxyz";
    char str2[] = "xyzabcd";
    
    findLCS(str1, str2);
    
    return 0;
}

Hope this helps!