c语言初学必背代码

1、printf("sum=%dn",sum);/1.成绩判断#include<stdio.h>intmain()/成绩intscore;printf("请输入你的成绩:n");scanf("%d",&score);/判断if(score>=0&&score<60)printf("不及格n");elseif(60<=score&&score<80)printf("中等n");elseif(80<=score&&

2、amp;score<100)printf("优秀n");elseprintf("输入错误!n");/3.最大公约数#include<stdio.h>/求m,n的最大公约数intmain()intm,n;inti,k;printf("请输入两个数:");scanf("%d%d",&m,&n);/三元运算符找较小的那个k=m<n?m:n;/从较小的那个数倒着往前找for(i=k;i>=1;i-)/这是公约数if(m%i=0)&&(n%i=0)printf(&

3、quot;最大公约数是%dn",i);break;/跳出for循环/4.最小公倍数/2.计算1到100的和#include<stdio.h>intmain()intsum=0;/存结果变量inti;for(i=1;i<=100;i+)sum=sum+i;#include<stdio.h>/求m,n的最小公倍数intmain()intm,n;intmax,min;/m,n中较大,较小的那个intk;/max,2*max,3*max,printf("请输入两个数:");scanf("%d%d",&m,&

4、n);/也可以交换m,n,保证m小n大max=m>n?m:n;min=m<n?m:n;k=max;/从max开始while(k%min!=0)k+=max;/每次倍增printf("最小公倍数是%dn",k);/5.金字塔#include<stdio.h>/金字塔intmain()inti;/外层intj;/内层for(i=1;i<=10;i+)/当前是在第i行/先补空格10-i个for(j=1;j<=10-i;j+)printf("");/再打2i-1个*for(j=1;j<=2*i-1;j+)printf(&

5、quot;*");printf("n");/6.九九乘法表#include<stdio.h>/打印九九乘法表intmain()inti,j;for(i=1;i<=9;i+)/外层一定是9行for(j=1;j<=i;j+)/内层第几行走几遍printf("%d*%d=%d",i,j,i*j);printf("n");/7.百钱买百鸡#include<stdio.h>/*百钱买百鸡,类似1,2,5凑100银币问题*/intmain2()inti,j;/公鸡，母鸡个数for(i=0;i<=

6、20;i+)/公鸡for(j=0;j<=33;j+)/母鸡if(15*i+9*j+(100-i-j)=300)printf("公鸡”母鸡,小鸡肝,i,j,100-i-j);sum+=ai;/1,2,5凑100银币问题intmain3()intcount=0;/情况数inti,j;/5分个数，2分个数for(i=0;i<=20;i+)/5分个数for(j=0;j<=50;j+)/2分个数if(5*i+2*j)<=100)count+;printf("%d:5分dj,2分个，1分djn",count,i,j,100-5*i-2*j);/8.一维

7、数组的最大值、最小值、平均值#include<stdio.h>#defineN10/宏定义常量intmain()inti;/下标索引intmax,min;doublesum=0;/累加和intaN=58,58,96,100,25,55,66,88,99,77;max=a0;/假设第一个最大min=a0;/假设第一个最小for(i=1;i<N;i+)if(ai>max)/比最大值还大max=ai;/你才是最大if(ai<min)/比最小值还小min=ai;/你才是最小printf("max=%d,min=%dn",max,min);printf(

8、"average=%.2lfn",sum/N);/9.二维数组的最大值、最小值、平均值#include<stdio.h>intmain()inti;/第几行intj;/第几列inta34=1,2,3,4,5,-6,7,8,9,19,39,0;intmax=a00;/假设你最大intmin=a00;/假设你最小doubleaverage;/平均值doublesum=0;/总和for(i=0;i<3;i+)/必定3行for(j=0;j<4;j+)/必定4列printf("%5d",aij);sum+=aij;if(aij>max

9、)max=aij;if(aij<min)min=aij;printf("n");average=sum/(3*4);printf("max=%d,min=%d,avg=%.2lfn",max,min,average);#include<stdio.h>/二维数组转置：行变列，列变行intmain()inti;/第几行intj;/第几列inta34=1,2,3,4,5,-6,7,8,9,19,39,0;intb43;for(i=0;i<3;i+)for(j=0;j<4;j+)printf("%5d",aij

10、);printf("n");/矩阵转置for(i=0;i<3;i+)for(j=0;j<4;j+)bji=aij;for(i=0;i<4;i+)for(j=0;j<3;j+)printf("%5d",bij);printf("n");#include<stdio.h>#defineN10/宏定义常量intmain()inti;/下标索引intj;inttmp;/临时交换用intaN=58,58,96,100,25,55,66,88,99,77;/外层循环一定是N-1for(i=0;i<N-1;

11、i+)/两两交换，大的往后走for(j=0;j<N-i-1;j+)/交换if(aj>aj+1)tmp=aj;aj=aj+1;aj+1=tmp;for(i=0;i<N;i+)printf("%d",ai);printf("n");#include <stdio.h>/12.结构冒泡排序/结构定义,用户自定义类型typedefstructstudentcharsno20;/学号charname20;/姓名intage;/年龄chargender;/性别chartel20;/电话;intmain()inti;intj;double

12、sum=0;structstudenttmp;/两两交换临时用;/结构数组structstudentteam5;for(i=0;i<5;i+)printf("请输入第dj队员的信息：n”,i+1);scanf("%s%s%d%c%s",teami.sno,,&teami.age,&teami.gender,teami.tel);/按年龄冒泡排序for(i=0;i<5;i+)for(j=0;j<5-i-1;j+)/两两交换if(teamj.age>teamj+1.age)tmp=teamj;teamj=te

13、amj+1;teamj+1=tmp;/取值printf("%-12s%-10s%-5s%-5s%-15sn","学号","姓名","年龄","性别","电话");for(i=0;i<5;i+)printf("%-12s%-10s%-5d%-5c%-15sn",teami.sno,,teami.age,teami.gender,teami.tel);/13.结构数组找年龄最大值#include<stdio.h>/结构定义

14、,用户自定义类型typedefstructstudentcharsno20;/学号charname20;/姓名intage;/年龄chargender;/性别chartel20;/电话;intmain()inti;structstudenttmp;/找最大临时用/结构数组structstudentteam5;for(i=0;i<5;i+)printf("请输入第%d个队员的信息:n",i+1);scanf("%s%s%d%c%s",teami.sno,,&teami.age,&teami.gender,teami

15、.tel);/取值printf("%-12s%-10s%-5s%-5s%-15sn","学号","姓名","年龄","性别","电话");for(i=0;i<5;i+)printf("%-12s%-10s%-5d%-5c%-n",teami.sno,,teami.age,teami.gender,teami.tel);/找学号最大的那一个tmp=team0;for(i=1;i<5;i+)if(strcmp(teami.sno

16、,tmp.sno)>0)tmp=teami;printf("学号最大的队员如下:n");printf("%-12s%-10s%-5d%-5c%-n",tmp.sno,,tmp.age,tmp.gender,tmp.tel);/14.文件读写#include<stdio.h>#include<stdlib.h>/结构定义,用户自定义类型typedefstructstudentcharsno20;/学号charname20;/姓名intage;/年龄chargender;/性别chartel20;/电话;/文件读

17、写intmain()structstudent*s,*p1;/个数未知FILE*fp;inti,n=0;charbuf1024;/fgets缓冲区/打开文件fp=fopen("e:test.txt","r");while(fgets(buf,1024,fp)!=NULL)n+;fclose(fp);/指向一个可以存储n个student结构的内存空间s=(structstudent*)malloc(sizeof(structstudent)*n);p1=s;/不要动头位置s的值/打开文件fp=fopen("e:test.txt",&qu

18、ot;r");for(i=0;i<n;i+)/从文件中读入一行fscanf(fp,"%s%s%d%c%s",p1->sno,p1->name,&p1->age,&p1->gender,p1->tel);p1+;fclose(fp);p1=s;for(i=0;i<3;i+)printf("%s%s%d%c%sn",p1->sno,p1->name,p1->age,p1->gender,p1->tel);free(s);/15.输入三角形三边长计算周长和面积#i

19、nclude<stdio.h>#include<math.h>intmain()doublearea,perimeter,s,a,b,c;printf("请输入三边长abc:");scanf("%lf%lf%lf",&a,&b,&c);if(a+b>c)&&(a+c>b)&&(b+c>a)s=(a+b+c)/2;area=sqrt(s*(s-a)*(s-b)*(s-c);perimeter=a+b+c;n",area,perimeter);else

20、printf("三边长无法构成三角形。n");return0;/16.输入年份和月份输出对应那一月的天数，要处理闰年#includeintmain()intyear,month;intleap=0;scanf("%d%d",&year,&month);if(year%4=0&&year%100!=0)|year%400=0)/闰年2月29天leap=1;switch(month)case1:case3:case5:case 7:case 8:case10:case12:printf("31");break;case4:case6:case9:case11:printf("30");break;case2:printf("%d",28+leap);break;default:printf("error");break;return0;/17.1，2，5分硬币问题#include<stdio.h>intmain()intsum=0;for(inti=0;