请用c++写出KMP算法下字符串匹配

好的，以下是使用C语言实现KMP算法进行字符串匹配的代码：

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

void getNext(char *pattern, int next[]) {
    int len = strlen(pattern);
    next[0] = -1;
    int i = -1, j = 0;
    while (j < len - 1) {
        if (i == -1 || pattern[i] == pattern[j]) {
            i++;
            j++;
            next[j] = i;
        } else {
            i = next[i];
        }
    }
}

int KMP(char *text, char *pattern) {
    int tlen = strlen(text);
    int plen = strlen(pattern);
    int next[plen];
    getNext(pattern, next);
    int i = 0, j = 0;
    while (i < tlen && j < plen) {
        if (j == -1 || text[i] == pattern[j]) {
            i++;
            j++;
        } else {
            j = next[j];
        }
    }
    if (j == plen) {
        return i - j;
    } else {
        return -1;
    }
}

int main() {
    char text[] = "ABABABCABAABABABAB";
    char pattern[] = "ABABAB";
    int pos = KMP(text, pattern);
    if (pos == -1) {
        printf("Pattern not found in text.\n");
    } else {
        printf("Pattern found at position %d in text.\n", pos);
    }
    return 0;
}

希望这个代码能够帮到你。如果你有更多问题，可以继续问我。