poj 3753 根据关键字进行字符串拷贝

#include <iostream>#include <string>using namespace std;int SafeStrcpy2KeyWord(char* pDestBuffer,          char* pSourceString,          int nDestBufferSize,          char* szKeyWord); int main() { char s1[300],s2[300],s3[300]; int len; while(scanf("%s",s1) !=EOF) {  while(scanf("%s",s2) && strcmp(s2,"END") != 0)  {   len = SafeStrcpy2KeyWord(s3,s1,300,s2);   if(len == 0)    printf("0 NULLn");   else    printf("%d %sn",len,s3);  } } return 0;}int SafeStrcpy2KeyWord(char* pDestBuffer,          char* pSourceString,          int nDestBufferSize,          char* szKeyWord) { if(nDestBufferSize == 0 || strcmp(szKeyWord,"NULL") == 0) {  return 0; } char *k = strstr(pSourceString,szKeyWord); if(k == NULL) {  strcpy(pDestBuffer,pSourceString);  return strlen(pSourceString); } if(k-pSourceString==0|| k-pSourceString > nDestBufferSize) {  return 0; } int i; for(i = 0;i < k-pSourceString; i++) {  pDestBuffer[i] = pSourceString[i]; } pDestBuffer[i] = 0; return i ;}