7-1 計(jì)算階梯水價(jià) ????????????????????????????????????????

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#include<stdio.h>

int main() {

??? float usage, fee;

??? scanf("%f", &usage);

??? if (usage <= 17) {

??????? fee = usage * 3.40;

??? } else if (usage <=30) {

??????? fee = 17 * 3.40 + (usage - 17) * 5.32;

??? } else {

??????? fee = 17 * 3.40 + 13 * 5.32 + (usage - 30) * 7.00;

??? }

printf("%.2f\n", fee);

??? return 0;

}

解方程

#include<stdio.h>

#include<math.h>

int main()

{

?????? float x1,x2;

?????? int a,b,c,delta;

?????? scanf("%d%d%d",&a,&b,&c);

?????? delta=pow(b,2)-4*a*c;

?????? if(delta==0){

????????????? printf("x=%.3f",(-1.0*b)/(2*a));

?????? }

?????? else if(delta>0){

????????????? x2=(-1.0*b+sqrt(delta))*1.0/(2*a);

????????????? x1=(-1.0*b-sqrt(delta))*1.0/(2*a);

????????????? printf("x1=%.3f\nx2=%.3f\n",x1,x2);

?????? }

??? else if(delta<0){

??????? printf("no real solution");

??? }

?????? return 0;

}

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求分?jǐn)?shù)序列前N項(xiàng)和

#include<stdio.h>

int main(){

??? int n,i;

??? double a=1,b=1,t=0,sum=0;

??? scanf("%d",&n);

??? for(i=1;i<=n;i++)

??? {

??????? t=b;

??????? b=a+b;

??????? a=t;

????? ??sum=sum+b/a;

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??? }

??? printf("%.2f",sum);

??? return 0;

}

求奇數(shù)

#include<stdio.h>

int main()

{

??? int n,sum=0;

??? scanf("%d ",&n);

??? while(n>0)

??? {

??????? if(n%2!=0)

??????? {

??????????? sum=sum+n;

??????? }

??????? scanf("%d ",&n);

??? }

??? printf("%d",sum);

??? return 0;

}

求整數(shù)的位數(shù)及各位數(shù)字之和

#include<stdio.h>

int main()

{

??? int a,b=0,c=0;

??? scanf("%d",&a);

??? while(a)

??? {

??????? b++;

??????? c+=a%10;

??????? a/=10;

??? }

??? printf("%d %d",b,c);

??? return 0;

}

7-6 猴子吃桃問(wèn)題

#include<stdio.h>

int main()

{

??? int n,s,i,x=1;

??? scanf("%d",&n);

??? for(i=1;i<=n;i++){

??????? s=x;

??????? x=2*(x+1);

??? }

??? printf("%d",s);

??? return 0;

}

7-7 打印菱形圖案

#include <stdio.h>

int main()

{

??? int n;

??? scanf("%d",&n);

??? n=(n+1)/2;

??? int i,j;

??? for(i=1;i<=n;i++)

??? {

??????? for(j=1;j<=2*(n-i);j++)

??????? {

??????????? printf(" ");

??????? }

??????? for(j=1;j<=2*i-1;j++)

??????? {

??????????? printf("* ");

??????? }

??????? printf("\n");

??? }

??? for(i=n-1;i>=1;i--)

??? {

??????? for(j=1;j<=2*(n-i);j++)

??????? {

??????????? printf(" ");

??????? }

??????? for(j=1;j<=2*i-1;j++)

??????? {

??????????? printf("* ");

??????? }

??????? printf("\n");

??? }

}

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7-8 換硬幣

#include<stdio.h>

int main(){

int x;

int i,j,k;

int count=0;

scanf("%d",&x);

for(i=x/5;i>0;i--)

????????????? for(j=x/2;j>0;j--)

???????????????????? for(k=x;k>0;k--)

?????? if(i*5+j*2+k*1==x){

?????? printf("fen5:%d, fen2:%d, fen1:%d, total:%d\n",i,j,k,i+j+k);

?????? count++;

}

printf("count = %d",count);

}

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7-9 最大公約數(shù)和最小公倍數(shù)

#include<stdio.h>

int main()

{

??? int m,n;

??? int gongyue,gongbei;

??? scanf("%d %d",&m,&n);

??? int flag;

??? if(m>n){flag = n;}else flag = m;

??? for(int x= 1;x<=flag;x++)

??? {

??????? if(m%x==0 &&n%x==0)

??????? {

??????????? gongyue = x;

??????? }

??? }

??

???

??? gongbei = m*n/gongyue;

???

??? printf("%d %d",gongyue,gongbei);

???

??? return 0;

}

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7-10 兔子繁衍問(wèn)題

#include<stdio.h>

int main()

{

?????? int x,i;

?????? int a=2, b=0, c=0;

?????? scanf("%d", &x);

?????? if (x > 1)

?????? {

????????????? for (i = 1; c < x; i++)

????????????? {

???????????????????? c = a + b;

???????????????????? b = a;

???????????????????? a = c;

????????????? }

???????

????????????? printf("%d", i+1);

?????? }

?????? else

????????????? printf("1");

?????? return 0;

}

7-10猜數(shù)字游戲

#include <stdio.h>

int main(){

??? // randNum：隨機(jī)數(shù)? guessNum：用戶猜測(cè)數(shù)? N：次數(shù)? flag：標(biāo)志

??? int randNum, guessNum, N, flag = 0;

???

??? scanf("%d %d", &randNum, &N);

???

??? for( int i=1; i<=N; i++ ){ //循環(huán)輸入N次結(jié)束

??????? scanf("%d", &guessNum);

???????

??????? if( guessNum < 0 )?? // 輸入不合法

??????????? break;

???????

??????? if( guessNum > randNum ) // 輸入太大

??????????? printf("Too big\n");

??????? else if( guessNum < randNum )? // 輸入太小

??????????? printf("Too small\n");

??????? else if( guessNum == randNum ){? // 相等

??????????? if( i == 1 )? // 1次成功

??????????????? printf("Bingo!\n");

??????????? else if( i <= 3 )? // 3次以內(nèi)成功

??????????????? printf("Lucky You!\n");

???????? ???else if( i > 3 )?? // 3次以上成功

??????????????? printf("Good Guess!\n");

??????????? flag = 1;

??????????? break;

??????? }

??? }

??? // 判斷是否在N次內(nèi)猜對(duì)

??? if( flag == 0 )

??????? printf("Game Over\n");

???

??? return 0;

}