【leetcode】415. 字符串相加

#define MAXLEN 6000
char * addStrings(char * num1, char * num2){
    char* arr=(char*)calloc(MAXLEN+1,sizeof(char));
    int right1=strlen(num1)-1, right2=strlen(num2)-1, flag=0, i, pst=MAXLEN, temp1, temp2;
    while(right1>=0 || right2>=0 || flag){
        temp1=(right1>=0)?num1[right1--] :'0';
        temp2=(right2>=0)?num2[right2--] :'0';
        arr[--pst]='0'+(temp1-'0'+temp2-'0'+flag)%10;
        flag=(temp1-'0'+temp2-'0'+flag >= 10)?1 :0;
    }
    return arr+pst;
}