c++编写一个程序,检查字符串s1是否是字符串s2的子串.如果s1是s2的子串,函数返回第一次匹

int findStr(char* str, char* tofind){ int i = 0, j = 0; while (str[i]!='\0') { while (tofind[j]!='\0') if (tofind[j] == str[i]) { i++; j++; } else { i -= j; j = 0; break; } if (j) return i-j; i++; } return -1