声明并赋初始值。j,k作为循环计数变量仅声明不赋初始值。

第一个循环j从1到4，控制打印行数；

内部循环从0到2*j-1(对应j分别取值1,3,5,7)，这个循环控制打印字符的个数；printf(" c",i) 这一句把i变量按相应的ASCII码对应的字符以字符形式打印出来；-Statement and to give the initial value. j, k as the loop counter not only to declare the initial value assigned. The first cycle j from 1 to 4, control print lines　internal loop from 0 to 2* j-1 (corresponding to j values 1,3,5,7, respectively), the loop control the number of printed characters　printf ( "　 c" , i)　this one the i variable by the corresponding ASCII character code corresponding to the characters to be printed