C语言程序设计入门源代码代码集合.doc

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演示1
#include <stdio.h>
void print_star(void)
{
printf("*****************\n");
}
void print_wele(void)
{
printf("C language,wele!\n");
}
void main()
{
print_star();
print_wele();
print_star();
getchar();
}

演示2

#include "stdio.h"
int sum(int i,int j)
{
return(i + j);
}
void main()
{
int n1,n2;
printf("input 2 numbers:\n");
scanf("%d%d",&n1,&n2);
printf("the sum = %d\n",sum(n1,n2));
getchar();
}

演示3

#include "stdio.h"
int maxnum(int,int,int);
main()
{
int a,b,c;
printf("Please enter 3 numbers:\n");
scanf("%d,%d,%d",&a,&b,&c);
printf("Maxnum is %d\n",maxnum(a,b,c));
return 0;
}
int maxnum(int x,int y,int z)
{
int max=x;
if(y>max)
max = y;
if(z>max)
max = z;
return max;
}

演示4

#include <stdio.h>
int s1(int n)
{
int j,s;
s=0;
for(j=1;j<=n;j++)
s=s+j;
return s;
}
int sum(int n)
{
int i,s=0;
for(i=1;i<=n;i++)
s=s+s1(i);
return s;
}
void main()
{
int n;
printf("n:");
scanf("%d",&n);
printf("s=%d\n",sum(n));
}

演示5

#include <stdio.h>
void func(int n)
{
int i;
for(i=n-1;i>=1;i--)
n=n+i;
printf("n=%d\n",n);
}
void main()
{
int n;
printf("Input n:");
scanf("%d",&n);
func(n);
printf("n=%d\n",n);
}

演示6

#include <stdio.h>
void swap(int a,int b)
{
int temp;
temp=a;a=b;b=temp;
printf("swap : a=%d,b=%d\n",a,b);
}
void main()
{
int a,b;
a=3;b=10;
swap(a,b);
printf("a=%d,b=%d\n",a,b);
}

演示7

#include <stdio.h>
int func(int a,int b)
{
int c;
c=a+b;
return c;
}
void main()
{
int x=6,y=7,z=8,r;
r=func((x--,y++,x+y),z--);
printf("%d\n",r);
}

演示8

#include <stdio.h>
max(float x,float y)
{
return x>y? x:y;
}
void main()
{
printf("%d\n",max(2,3.5));
}

演示9

#include <stdio.h>
int sum(int n)
{
int i,s=0;
for(i=0;i<=n;i++)
s=s+i;
return s;
}
void main()
{
int m,sn;
scanf("%d",&m);
sn=sum(m);
printf("the sum is %d\n",sn);
}

演示10
#include <stdio.h>
void swap(int x,int y);
int main()
{
int a,b;
printf("input 2 numbers :\n");
scanf("%d,%d",&a,&b);
printf("input number is:a=%d,b=%d \n",a,b);
swap(a,b);
printf("input 2 numbers is:a=%d,b=%d\n",a,b);
return 0;
}
void swap(int x,int y)
{
int temp;
temp = x;
x = y;
y = temp;
printf("swap number is : x = %d,y = %d \n",x,y);
}

演示11

#include "stdio.h"
#define K 3
#define N 5
long f2(int n,int k)
{
long power = n;
int i;
for(i=1;i<k;i++)
power *=n;
return power;
}
long f1(int n,int k)
{
long sum = 0 ;
int i;
for(i=1;i<=n;i++)
sum = sum + f2(i,k);
return sum;
}
int main(void)
{
printf("sum of %d power of integer from 1 to %d = ",K,N);
printf("%ld\n",f1(N,K));
return 0;
}
演示12

#include <stdio.h>
int min(int a,int b);
int main(void)
{
int j,k,mininum;
printf("input 2 integers:");
scanf("%d,%d",&j,&k);
mininum = min(j,k);
printf("\n of the two values %d and %d,the mininum is %d\n",j,k,mininum);
return 0;
}
int min(int a,int b)
{
if(a<b)
return a;
else
return b;
}

演示13
#include <stdio.h>
int func(int a,int b);
void main()
{
int k=4,m=1,p;
p=func(k,m);
printf("%d\n",p);
}
int func(int a,int b)
{
int m=0,i=2;
i+=m+1;
m=i+a+b;
return m;
}

演示14
#include <stdio.h>
int max(int x,int y)
{
int z;
z=x>y?x:y;
return z;
}
void main()
{
extern int A,B; //声明外部变量
printf("%d\n",max(A,B));
}
int A=13,B=-8; //定义外部变量

演示15
#include <stdio.h>
int f1(int xb)
{
extern int xa;
return (xa*xb);
}
int main(void)
{
extern int xb;
int xa = 5;
printf("xa=%d,xb=%d,result=%d",xa,xb,f1(xa));
return 0;
}
int xa = 3,xb = 4;

演示16
#include <stdio.h>
void num()
{
extern int x,y;
int a=15,b=10;
x=a-b;
y=a+b;
}
int x,y;
void main()
{
int a=7,b=5;
x=a+b;y=a-b;
num();
printf("%d,%d\n",x,y);
}

演示17
#include <stdio.h>
void main()
{
void swap();
extern int a,b;
a=3;
b=10;
swap();
printf("a=%d,b=%d\n",a,b);
}
int a,b;
void swap()
{
int temp;
temp=a;a=b;b=temp;
}
演示18

#include <stdio.h>
void auto_static(void)
{
int var_auto = 0;
static int var_static = 0;
printf("var_auto = %d,var_static = %d\n",var_auto++,var_static++);
}
void main()
{
int i;
for (i=0;i<3;i++)
auto_static();
}

演示19
#include <stdio.h>
void swap(int x,int y)
{
int t;
t=x;x=y;y=t;
}
void main()
{
int a,b;
scanf("%d,%d",&a,&b);
swap(a,b);
printf("%d,%d\n",a,b);
}
----------------------------------------------------------------------------------------------------------
#include <stdio.h>
int x,y;
void swap(int ，,int)
{
int t;
t=x;x=y;y=t;
}
void main()
{

scanf("%d,%d",&x,&y);
swap(x,y);
printf("%d,%d\n",x,y);
}
#include <stdio.h>
int x,y;
void swap(int x,int y)
{
int t;
t=x;x=y;y=t;
}
void main()
{
scanf("%d,%d",&x,&y);
swap(x,y);
printf("%d,%d\n",x,y);
}
----------------------------------------------------------------------------------------------------------------------
演示20
#include <stdio.h>
int fac(int n)
{
static int f=1;
f=f*n;
return f;
}
void main()
{
int i;
for(i=1;i<=5;i++)
printf("%d!=%d\n",i,fac(i));
}

演示21
#include "stdio.h"
int main(void)
{
int a = 2;
int p = a;
printf("%d\n",a);
{
int a =7;
printf("%d\n",a);
printf("%d\n",p);
}
printf("%d\n",++a);
return 0;
}

演示22

#include <stdio.h>
int func(int a,int b);
void main()
{
int k=4,m=1,p;
p=func(k,m);printf("%d,",p);
p=func(k,m);printf("%d\n",p);
}
int func(int a,int b)
{
static int m=0,i=2;
i+=m+1;
m=i+a+b;
return m;
}

演示23
#include <stdio.h>
f(int n)
{
int c;
if(n==6)c=1;
else
c=(f(n+1)+1)*2;
return c;
}
void main()
{
printf("%d\n",f(1));
}

演示24

#include <stdio.h>
long power(int n)
{
long f;
if(n>1)
f=power(n-1)*n;
else
f=1;
return f;
}
main()
{
int n;
long x;
printf("input an integer number:\n");
scanf("%d",&n);
x=power(n);
printf("%d!=%ld\n",n,x);
getchar();
}

演示25
#include <stdio.h>
int fact()
{
static int i=5;
if(i==0) return 1;
else
{
i--;
return (i+1)*fact();
}
}
void main()
{
printf("fact=%d\n",fact());
}

演示26
#include <stdio.h>
int fun(int k);
int w=3;
void main()
{
int w=10;
printf("%d\n",fun(5)*w);
}
int fun(int k)
{
if(k==0) return w;
return(fun(k-1)*k);
}

演示27

#include <stdio.h>
int fac(int n)
{
register int i,f=1;
for(i=1;i<=n;i++)
f=f*i;
return f;
}
main()
{
int i;
for(i=1;i<=5;i++)
printf("%d!=%d\n",i,fac(i));
}

演示28

#include <stdio.h>
age(int n)
{
int c;
if(n==1)c=10;
else
c=age(n-1)+2;
return c;
}
void main()
{
printf("%d\n",age(5));
}

演示29
#include <stdio.h>
#define PI 3.14
#define circuit(r) 2*PI*r
#define area(r) PI*r*r
void main()
{
float ra,c,a;
scanf("%f",&ra);
c=circuit(ra);
a=area(ra);
printf("ra=%f,c=%f,a=%f",ra,c,a);
}

汉诺塔〔演示30〕
#include "stdio.h"
void move(int,char,char,char);
int main(void)
{
int n;
printf("input n disk on tower A:\n");
scanf("%d",&n);
move(n,'A','B','C');
getchar();
return 0;
}
void move(int n,char a,char b,char c)
{
static int step=1;
if(n==1)
{
printf("step %d :move disk form %c -> %c\n",step++,a,c);
}
else
{
move(n-1,a,c,b);
move(1,a,b,c);
move(n-1,b,a,c);
}
}

演示31
#define LETTER 1
#include "stdio.h"
void main()
{
char str[20]="C Language",c;
int i;
i=0;
while((c=str[i])!='\0')
{
i++;
#if LETTER
if(c>='a'&&c<='z')
c=c-32;
#else
if(c>='A'&&c<='Z')
c=c+32;
#endif
printf("%c",c);
}
}

#include <stdio.h>
long f(int n)
{
if(n==1||n==2)
return 1;
else
return f(n-1)+f(n-2);
}
void main()
{
long n;
printf("input n:\n");
scanf("%d",&n);
printf("the number is %d\n",f(n));
}
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