任务3

#include<stdio.h>
#include<stdlib.h>
#include<math.h>
int is_prime(int s);
int main(){
    int n;
    int a,b;
    for(n=4;n<=20;n=n+2){
        for(a=2;a<=n;a++){
             b=n-a;
            if(is_prime(a)&&is_prime(b)){
             printf("%d=%d+%d\n",n,a,b);break;
              }
              
              }
            }
    return 0;
}

int is_prime(int s){
    int m;
    for(m=2;m<=s-1;m++){
            if(s%m==0) return 0;
            if(m>=s) return 1;
            }
    }

#include<stdio.h>
long fun(long s);
int main(){
    long s,t;
    printf("Enter a number:");
    while(scanf("%ld",&s)!=EOF){
        t=fun(s);
        printf("new number is:%ld\n\n",t);
        printf("Enter a number: ");
    } 
    return 0;
} 

long fun(long n){
    int m;
    int t=0,q=1;
    while(n>0){
        n=n/10;
        m=n%10;
        if(m%2!=0){
            t=t+m*q;
            q=q*10;
        }
        
    }return t;
}

#include <stdio.h>
int func(int, int); 
int main() {
int k = 4, m = 1, p1, p2;
p1 = func(k, m); 
p2 = func(k, m); 
printf("%d, %d\n", p1, p2);
return 0;
}
int func(int a, int b) {
static int m = 0, i = 2;
i += m + 1;
m = i + a + b;
return m;
}

局部static变量保留变量改变后的值。

#include<stdio.h>
long long func(int n);

int main(){
    int n;
    long long f;
    while(scanf("%d",&n)!=EOF){
        f=func(n);
        printf("n=%d,f=%lld\n",n,f);
    }
    return 0;
} 
int long long func(int n){
if(n==0){
return 0;
}
if(n==1){
return 1;
}
if(n>1){
return 2*func(n-1)+1;
}
}

#include<stdio.h>
int func(int n,int m);

int main(){
    int n,m;
    while(scanf("%d%d",&n,&m)!=EOF)
    printf("n=%d,m=%d,ans=%d\n",n,m,func(n,m));
    return 0;
} 
int func(int n,int m){
if(n<m){
    return 0;
}
if(n==m||m==0){
    return 1;
}
if(m==1){
    return n;
}
if(n>m&&n>=2){
    return func(n-1,m)+func(n-1,m-1);
}
}

#include<stdio.h>
int mul(int n,int m);
int main(){
    int n,m;
    while(scanf("%d%d",&n,&m)!=EOF)
    printf("%d*%d=%d\n",n,m,mul(n,m));
    return 0;
} 
int mul(int n,int m){
    if(m==0){
    return 0;
    }
    if(m==1){
    return n;
    }
    if(m>=2){
    return n+mul(n,m-1);
    }

}

#include<stdio.h>
#include<stdlib.h>
void hanoi(unsigned int n,char from,char temp,char to);
void moveplate(unsigned int n,char from,char to);
int main()
{
    unsigned int n,s;
    while(scanf("%u",&n)!=EOF){
    
    hanoi(n,'A','B','C');
        printf("\n");
    s=pow(2,n)-1;
    printf("一共移动了%d次\n",s);
    system("pause");
    }

    return 0;
}
void hanoi(unsigned int n,char from,char temp,char to)
{
    if(n==1)
    moveplate(n,from,to);
    else{
        hanoi(n-1,from,to,temp);
        moveplate(n,from,to);
        hanoi(n-1,temp,from,to);
    }
}
void moveplate(unsigned int n,char from,char to)
{
    printf("%u:%c-->%c\n",n,from,to);
}

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <windows.h>
#define N 80
void print_test(int line,int col,char test[]);
void print_spaces(int n);
void print_blank_lines(int n); 
int main() {
int line, col, i;
char text[N] = "hi, November~";
srand(time(0)); // 
for(i = 1; i <= 10; ++i) {
line = rand() % 25;
col = rand() % 80;
print_text(line, col, text);
Sleep(1000); 
}
return 0;
}

void print_spaces(int n) {
    int i;
for(i = 1; i <= n; ++i)
printf(" ");
}
void print_blank_lines(int n) {
int i;
for(i = 1; i <= n; ++i)
printf("\n");
}
void print_text(int line, int col, char text[]) {
print_blank_lines(line-1); 
print_spaces(col-1); 
printf("%s", text); 
}

在第line行第col列输入"hi,November~"