推荐大家先在本地编写并运行后再上传至头歌平台

推荐使用Visual Studio,VS code,CLion等现代化IDE，拥有代码自动高亮，错误提示，自动补全等功能

第一道

#include<stdio.h>
	int main(void)
	{  
	  int a,b,c; 
	  /*********Begin*********/
	  scanf("%d,%d",&a,&b);
      c = a + b;
      printf("%d+%d=%d\n",a,b,c);
	  
	  /*********End**********/ 
       return 0;
	}

第二道

#include<stdio.h>
	int main(void)
	{  
	  int a,b;
	  //Enter a and b:
      scanf("%d%d",&a,&b); 
      printf("a=%d b=%d\n",a,b);
	  /*********Begin*********/
	  a = a + b;
      b = a - b;
	  a = a - b;

	  
	  /*********End**********/
	  printf("a=%d  b=%d\n",a,b);  
       return 0;
	}

第三道

#include<stdio.h>
	int main(void)
	{  
	  /*********Begin*********/
	   int x,c;
	   scanf("%d",&x);
	   c=30 * x;
	   printf("%d",c);
	  
	  /*********End**********/ 
       return 0;
	}

第四道

#include<stdio.h>
	int main(void)
	{  
	  /*********Begin*********/
	  int n,a,b,c;
      scanf("%d",&n);
      a = (n / 100) % 10 ;
      b = (n / 10) % 10 ;
      c = n % 10 ;
      printf(" %d %d %d \n",a,b,c);

	  
	  /*********End**********/ 
       return 0;
	}

第五道

#include<stdio.h>
	int main(void)
	{  
	  /*********Begin*********/
	 int a,b,c,d,e,sum;
	  float avg;
	  scanf("%d %d %d %d %d",&a,&b,&c,&d,&e);
	  sum = a+b+c+d+e;
	  avg = sum/5.00;
	  printf("%d %.2f",sum,avg);

	  /*********End**********/ 
       return 0;
	}

第六道

#include<stdio.h>
#include<math.h>
	int main(void)
	{  
	  /*********Begin*********/
      float a,b,c,s,area;
      scanf("%f %f %f",&a,&b,&c);
      s = ( a + b + c ) / 2;
      area =  sqrt( s * ( s - a ) * ( s - b ) * ( s - c ) );
      printf("%.3f\n",area);

	  
	  
	  /*********End**********/ 
       return 0;
	}

第七道

#include<stdio.h>
	int main(void)
	{  
	  /*********Begin*********/
	#define PI 3.14
	double r,h,C1,Sb,Vb;
	scanf("%lf,%lf",&r,&h);

	C1= 2*PI*r;
	Sb= 4*PI*r*r;
	Vb= PI*r*r*h;
	printf("C1=%.2f\nSb=%.2f\nVb=%.2f\n",C1,Sb,Vb);

    
	  /*********End**********/ 
       return 0;
	}

第八道

#include<stdio.h>
int MaxCommonFactor( int a, int b)
{ 
   int c; 
   if(a<=0||b<=0) 
      return -1; 
   while(b!=0)
   { 
     c=a%b; 
     a=b;
     b=c;
   } 
  return a; 
}   
int main(void)
	{  
	  /*********Begin*********/
    int x,y,c;
    scanf("%d,%d",&x,&y);
    c = MaxCommonFactor(x,y);
    printf("%d\n",c);


	  
	  
	  /*********End**********/ 
    return 0;
}

进阶1

/*****************begin******************/
#include <stdio.h>

int main(){
  char w;

  w = getchar();
   printf("  %c\n",w);
   printf(" %c%c%c\n",w,w,w);
   printf("%c%c%c%c%c\n",w,w,w,w,w);
   printf(" %c%c%c\n",w,w,w);
   printf("  %c\n",w);

    return 0;
}
/*****************end******************/

进阶2

/***************begin*****************/
#include <stdio.h>

int main(){
    char c1,c2,c3,c4,c5;

    scanf("%c",&c1);
    scanf("%c",&c2);
    scanf("%c",&c3);
    scanf("%c",&c4);
    scanf("%c",&c5);
    
    printf("%c%c%c%c%c",c1+4,c2+4,c3+4,c4+4,c5+4);

    return 0;
}

/***************end*****************/

进阶3

/***************begin*****************/
#include <stdio.h>


int main(){
    int num,numa9;
    int g,s,b,q;
    scanf("%d",&num);
    q = (num / 1000) % 10 ;
    b = (num / 100) % 10 ;
    s = (num / 10) % 10 ;
    g = num % 10 ;

    q = q + 9;
    b = b + 9;
    s = s + 9;
    g = g + 9;

    q = q%10;
    b = b%10;
    s = s%10;
    g = g%10;
 
    b=b+g;
    g=b-g;
    b=b-g;

    q=q+b;
    b=q-b;
    q=q-b;

    numa9 = s*1000 + q*100 + b*10 +g;
    printf("The encrypted number is %d",numa9);

}
/***************end*****************/

进阶4

/************begin******************/
#include <stdio.h>
#include <math.h>

int main(){

float d, p, m, r;

r = 0.015;
p = 7000.0;
d = 400000.0;

scanf("%f,%f,%f", &d, &p, &r);
m = log10(p / (p - d * r)) / log10(1 + r); 

printf("%.1f月能还清",m);

return 0;
}
/***************end****************/