FOR循环 ，大家帮忙看看

#include <stdio.h>
int main(){
int i,j,n=13;
for(i=-n;i<=n;++i){
for(j=-n;j<=n;++j)
putchar(abs(i)+abs(j)<=n?'*':' ');
putchar('\n');
}
for(i=-n;i<=n;++i){
for(j=-n;j<=n;++j)
putchar(abs(i)+abs(j)==n?'*':' ');
putchar('\n');
}
for(i=-n;i<=n;++i){
for(j=-n;j<=n;++j)
putchar(abs(i)+abs(j)<=n&&abs(i)+abs(j)&1?'*':' ');
putchar('\n');
}
for(i=-n;i<=n;++i){
for(j=-n;j<=n;++j)
putchar(abs(i)+abs(j)<=n&&(abs(i)+abs(j))%3==1?'*':' ');
putchar('\n');
}
for(i=-n;i<=n;++i){
for(j=-n;j<=n;++j)
putchar(abs(i)+abs(j)<=n&&(abs(i)+abs(j))%5>=2?'*':' ');
putchar('\n');
}
for(i=-n;i<=n;++i){
for(j=-n;j<=n;++j)
putchar(abs(i)+abs(j)<=n&&abs(abs(i)-abs(j))%5>=2?'*':' ');
putchar('\n');
}
for(i=-n;i<=n;++i){
for(j=-n;j<=n;++j)
putchar(abs(i)+abs(j)<=n&&abs(abs(i)-abs(j))%5>=2&&(abs(i)+abs(j))%5>=2?'*':' ');
putchar('\n');
}
return 0;
}

贴吧里找的