C语言编程，快!!

如下(输出从A到Z循环):
#include<stdio.h>

int main()
{
char str[]={'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'};
int i=0;
int j=0;
int n=1;
int num;
printf("输入行数：");
scanf("%d",&num);

for(i=0;i<num;i++)
{
for(j=i;j<i+n;j++)
{
printf("%c ",str[(j%26)]);
}
printf("\n");
n++;
}
getch();
}

#include <stdio.h>

int main(void)
{
int n = 4;
int i, j;

printf("input the number of line: "