初学C语言常用简单程序代码

初学 C 语言常用简单程序代码素数的筛选#include #include #define N 1000int main(int argc, char* argv)int i,j,numN;for(i=0;iN;i+)numi=i+1;for(i=1;i(int)sqrt(double)N);i+) if(numi)for(j=i+1;jN;j+) if(numj) if(numj%numi=0) numj=0;for(i=1;iN;i+) if(numi)printf( %d,numi);return 0;输出时分秒#include main()int x,s,t,d;scanf(%d,&x);s=x%60;t=(x/60)%60;d=(x/60)/60;printf(%d 时d 分d 秒”4娟)；三个数的交换#include void main()int a,b,c,t;scanf(%d%d%d,&a,&b,&c);printf(The original number:a=%d,b=%d,c=%dn,a,b,c);t=a,a=b,b=t;t=a,a=c,c=t;printf(after swap:a=%d,b=%d,c=%d,a,b,c);switch语句的运用#include main()int a,m;printf(please input a number:);scanf(%d,&a);switch(a/10)case 10:case 9: m=5; break;case 8: m=4; break;case 7:m=3; break;case 6:m=2; break;default:m=1;printf(m=%d,m);判断奇数和偶数#include main()int x;printf(Please input a number: );scanf(%d,&x);if(x%2=0)printf(this is a oushu!);elseprintf(this is a jishu!);小写改大写，假设是大写那么不变include main()char c1,c2;printf(Input a lettern);scanf(%c,&c1);c2=(a=c1&c1=z)(c1-a+A):c1;printf(%c,c2);getchar();return 0;输入一个数，输出这个数是几位数#include main()int x,n;printf(please input a number:);scanf(%d,&x);n=0;while(x!=0)x=x/10;n+;printf(%d,n);输入一个数，判断它是几位数，然后逆序输出#includeint main()int num;int len =0;int temp =0;printf(Please input a number:n); scanf(%d,&num);while(num %10)!=0)temp =temp*10+(num%10);len+;numnum/10;printf(length =%dn,len);printf(Reverse is %d, temp);打印水仙花数#include main()int x, a,b,c;for(x=100;x=999;x+)a=x%10;b=(x/10)%10;c=x/100;if(x=a*a*a+b*b*b+c*c*c)printf(%5d,x); printf(n);判断闰年#include stdio.hmain()int k,flag,n=0;for(k=1980;k=2880;k+)flag=(k%4=0)&(k%100!=0)|(k%400=0); if(flag) printf(%5d,k);n+;if(n%10=0)printf(n);printf(n);求 1-3+5-7.-99+101的值#include main()int sum,i,t;sum=1;t=1;for(i=3;i=101;i=i+2)t=-t;sum=sum+t*i;printf(sum=%d,sum);求前 n 项和#include main()float s,t;int n,i,fz,fm;s=0;fz=2;fm=1;printf(Enter n:);scanf(%d,&n);for(i=1;i=n;i+)t=(1.0*fz)/fm;s=s+t;fz=fz+fm;fm=fz-fm;printf(s=%fn,s);开发一个程序求全班学生某门课的平均成绩， 要求程序每次运行时班级人数可为任意/* 用标记值来指示数据输入的完毕 */#include main()float average,total;int counter,score;total=0.0;counter=0;printf(输入成绩,-1表示完毕:)；scanf(%d,&score);while(score!=-1)/* 用-1 表示输入的完毕,同时循环输入分数 */ total=total+score;counter+;printf(输入下一个成绩,-1表示输入完毕：);scanf(%d,&score);if(counter!=0)average=total/counter;printf(全班平均成绩为：.2fn,average);elseprintf(没有输入成绩n);return 0;求二元一次方程的根#include #include main()float a=4,b=-40,c=91;float x1,x2;float delta;delta=sqrt(b*b-4.0*a*c);x1=(-b+delta)/(2.0*a);x2=(-b-delta)/(2.0*a);printf(x1=%f x2=%fn,x1,x2);if 语句的运用#include main()int a,b,c,s,w,t;s=w=t=0;a=-1;b=c=3;if(c0)s=a+b;if(a0)if(c0)w=a-b;elset=c;printf(s=%d, w=%d,t=%d,s,w,t);输入学生的生日，输出他的实足年龄#include main()int y0,m0,d0,y1,m1,d1,age;printf(nplease input birthday (yyyy/mm/dd):);scanf(%d/%d/%d ,&y0,&m0,&d0);printf(nplease input current day(yyyy/mm/dd):);scanf(%d/%d/%d ,&y1,&m1,&d1);if(m1m0) | (m1=m0 & d1=d0)age=y1-y0;elseage=y1-y0-1;printf(age=%d n,age);指针变量作为函数参数，实现两数的交换#include void sswap(int *x,int *y);main()int a=10,b=20;printf(before swap:a=%d,b=%dn,a,b);sswap(&a,&b);printf(after swap:a=%d,b=%dn,a,b);void sswap(int *x,int *y)int t;t=*x;*x=*y;*y=t;通过函数调用输出两个实型数中最大的一个#include float *f(float *px,float *py)if(*px*py)return px;return py;main()float x=10.0,y=20.0,*a=&x,*b=&y;printf(*a=%f,*b=%f,max=%fn,*a,*b,*f(a,b);计算并输出一个数组中所有元素的和，最大值，最小值，值为奇数的元素个数编写一个函数，将一个字符串中的字符全部转成大写#include void Lower2Upper(char *str)char *p=str;while(*p!=0)if(*p=a) *p=*p-32;p+;main()char s10=Hello!;int i;Lower2Upper(s);for(i=0;i10;i+)printf(%c,si);计算一个字符在一个字符串中出现的次数#include int count(char ch,char *str)char *p=str;int num=0;while(*p!=0)if(*p+=ch)num+;return num; main() char ah=a;char s=haowareayou;printf(the number is:);printf(%dn,count(a,s);删除一维数组中所有一样的数#include void unique(int *a,int *n)int k=1;int i,m;m=a0;for(i=0;im)ak+=ai; m=ai;*n=k;main()int a10;int n=10,i;printf(input a list number:); for(i=0;in;i+) scanf(%d,&ai);printf(Before delete:.n); for(i=0;in;i+) printf(%d,ai);unique(a,&n);printf(after deleten);for(i=0;in;i+) printf(%d,ai);printf(n);将字符串按字典顺序输出#include #include # define N 5void sort(char *name,int n);void prn(char *name,int n);void main()char *name=China,America,Australia,France,German;sort(name,N);prn(name,N);void sort(char *name,int n)char *pt;int i,j,k;for(i=0;in-1;i+)k=i;for(j=i+1;j0)k=j;if(k!=i)pt=namei;namei=namek;namek=pt; void prn(char *name,int n)int i;for(i=0;in;i+)printf(%sn,namei);有 n 个学生，每个学生考m 门课程，要求编一程序，能检查 n 个学生有无不及格的课程，如果有某一学生有一门或一门以上课程不及格，就输出该学生的和其全部成绩#include # define N 5# define M 4,int col);void prt(float *s,int no,int len);main()floataNM=78,99,89,87,67,59,87,77,86,53,59,95,77,88,57,95,78,75, 87,95;score(a,N,M);void score(float (*p)M,int row,int col)int i,j;int passed;for(i=0;irow;i+)passed=1;for(j=0;jcol;j+)if(pij60.0)passed=0;if(!passed)prt(pi,i,col);void prt(float *s,int no,int len)float *p;printf(NO.%d,no);for(p=s;ps+len-1;p+) printf(%5.1f,*p);printf(n);