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#ʵÏÖ¡¡int ºÍ¡¡string Ö®¼äµÄÏ໥ת»¯

１．ÏȽ«int תstring

char t[256];
sprintf(t,"%d",root->val);
string s = t;
str=str+s+",";

2.ÔÙ½«¡¡string תint

int a = atoi(t.c_str())