定义一个函数，返回其整数变元的字符串表示

void itoa ( n,char *s) { int i = 0, j, temp, sign; if((sign = n) < 0) { n = -n; } do { s[i++] = n%10 + '0'; }while ((n /= 10) > 0); if(sign < 0) s[i++] = '-'; s[i] = '\0'; for (j = 0;