6.3 使用嵌套循環(huán)輸出下列圖案

F

FE

FED

FEDC

FEDCB

FEDCA

6.4 要求用戶輸入一個(gè)大寫(xiě)字母，使用嵌套循環(huán)產(chǎn)生金字塔圖案#include<stdio.h>int main(){char ch;int i,j;int len;printf("請(qǐng)輸入一個(gè)大寫(xiě)字母/n");scanf("%c",&ch);if(ch>'Z'||ch<'A'){printf("input error！/n");   return 0;}len=ch-'A'+1; for(i=0;i<len;i++)    //控制行數(shù){for(j=0;j<len-i-1;j++) // 顯示空格printf(" ");for(j=0;j<=i;j++)     //顯示升序部分printf("%c",j+'A');for(j=i-1;j>=0;j--)   //顯示降序部分printf("%c",j+'A');printf("/n");}return 0;}

6.11 求兩個(gè)無(wú)限序列的和，直到達(dá)到某個(gè)次數(shù)。由用戶交互的輸入次數(shù)。

1.0+1.0/2.0+1.0/3.0+.....

1.0-1.0/2.0+1.0/3.0+......#include<stdio.h>//#include<math.h>double sum1(int);double sum2(int);int main(){int times;double total;int select;do{printf("please select method! input 1 or 2/n");scanf("%d",&select);printf("please input times/n");scanf("%d",&times);if(select==1){total=sum1(times);}else if(select==2){    total=sum2(times);}   else    {  printf("input error!/n");   }   printf ("the sum is  %f/n",total);}while(times!='#'); return 0;}//計(jì)算第一個(gè)表達(dá)式的值double sum1(int times){double sum=1.0;int i;for(i=1;i<times;i++){sum=sum+ 1/(double)(i+1);}return sum;}//計(jì)算第二個(gè)表達(dá)式的值double sum2(int times){double sum=1.0;int i;for(i=1;i<times;i++){if(i%2 == 0)sum=sum+1/(double)(i+1);else sum=sum-1/(double)(i+1);}return sum;}