C/C++学习笔记[01].纵向打印整数

#include <stdio.h>#include <string.h>#include <math.h>#define BASE 10int intlen(long n);int main(){ int i, j, num, sz; i = j = num = sz = 0; if (!scanf("%d", &num) || num <= 0) { printf("invalid input/n"); return 1; } sz = intlen(num); for (i = sz; i > 0; i--) { for (j = 1; j <= num; j++) { printf("%d",(j % (int) (pow(BASE,i))) / (int) (pow(BASE,i - 1))); } printf("/n"); } return 0;}int intlen(long n) { return log10(fabs(n)) + 1; }/* vim: set ts=4 sw=4: */

 

从标准输入接收一个大于0的整数,竖向打印1-这个数之间的数

用到了对数函数取整数的位数,取模运算,整除运算,指数运算