给定字符串A和B,输出A和B中的最大公共子串。     比如A="aocdfe" B="pmcdfa" 则输出"cdf"

void commonstring(char *str1, char *str2, char *maxSubstr)
{int i = 0, j = 0, k = 1, maxPos = -1, maxLen = 0;if ((NULL == str1) || (NULL == str2) || (NULL == maxSubstr)) {return NULL;} for (i=0; i < strlen(str1); i++){for (j=0; j < strlen(str2); j++){if (str1[i] == str2[j]){for (k=1; (str1[i+k] == str2[j+k]) && (str1[i+k]!='\0'); k++);}if (k > maxLen){maxPos = i;maxLen = k;}}}if (-1 == maxPos){maxSubstr[0] = '\0';}else{memcpy(maxSubstr, str1+maxPos, maxLen);maxSubstr[maxLen] = '\0';}
}