笔试练习题

字符串操作：不调用任何系统函数，实现一个字符串查找子串的函数，如果包含字串，则返回该字符串的位置值，如果不包含，则返回-1。

//查找子串#include <iostream>using namespace std;#define CM_ERROR  -1;int findSub(char* pSrc,char* pDes){if(NULL == pSrc || NULL == pDes){//pDes = "\0";return CM_ERROR;}int iPos = 1;char* pTmp;while('\0' != *pSrc){        pTmp = pDes;while(*pSrc != *pTmp){if(*pSrc == '\0'){return CM_ERROR;}pSrc++;iPos++;}while((*pSrc == *pTmp)&&('\0' != *pTmp)){pSrc++;pTmp++;}if(*pTmp !='\0'){iPos += 1;}elsebreak;}if(*pTmp=='\0'){return iPos;}elsereturn CM_ERROR;}int main(int argc, char const *argv[]){char chSrc[]= "hello world";char chDes[] = "ldd";int iPosition = findSub(chSrc,chDes);cout<<iPosition<<endl;system("pause");return 0;}