Chapter 1: drinking soft drinks, step tariff calculation, step tariff calculation function, personal income tax, solving square root inequality, simplifying solving square root inequality, solving dem

// Drink soda 
int main()
{
    
	long m, t, x, y;
	printf(" Please enter the number of people :");
	scanf("%d", &m);
	x = m / 20;
	t = m - 20 * x;
	y = t / 3;
	t = m - 20 * x - 3 * y;
	printf(" drink %ld Bottle of soda , Need at least %.2f element ", m, (13 * x + 2 * y) * 1.4 + t);
	return 0;
	
}

The verification results ：

// Step tariff calculation 
int main()
{
    
    double x,y;
    printf("  Please input the monthly electricity consumption （ degree )：");
    scanf ("%lf", &x); 
    if( x <= 240) //1/ branch 3 Gear meter  
    y = x * 0.49;
    else if (x <= 400) 
     y= 240 * 0.49 + (x - 240) *0.54;
    else 
     y = 240 * 0.49 +(400-240) *0.54 + (x - 400) *0.79;
    printf("  Electricity fee payable （ element ）：%9.2f\n",y);
    return 0;
}

result ：

// Step tariff calculation function 
 double f (double x)
 {
    
    double y; 
    if (x <= 240) 
       y= x * 0.49;
    else if (x <= 400) 
       y=f (240) + (x-240) *0.54; // Call its own function 
    else y=f (400) + (x-400) *0.79;
     return (y); // Return the electricity price 

 }
int main()
{
    
    double x;
    printf("  Please input the monthly electricity consumption ： ");
    scanf("%lf", &x);
    printf(" Electricity fee payable  %9.2f\n",f(x));

    return 0;
}

result ：

// Individual income tax 
double s(double x)
{
    
    double y, c, d;
    d=0;
     c=3500+d; 
     if (x<=c) y=0; 
     else if (x-c <= 1500) 
	 	y= (x-c) *0.03;
      else if (x-c <= 4500) 
	  	y=s (c+1500) + (x-c-1500) *0.10; 
      else if (x-c <= 9000) 
	  	y=s(c+4500) + (x-c-4500) *0.20; 
      else if (x-c <= 35000)
	  	 y=s (c+9000) + (x-c-9000) *0.25; 
      else if (x-c <= 55000)
	  	 y=s (c+35000) + (x-c-35000) *0.30; 
      else if (x-c <= 80000) 
	  	y=s (c+55000) + (x-c-55000) *0.35; 
      else 
	  	y =s(c + 80000) + (x-c-80000) *0.45; 
      return (y) ;
}
int main()
{
    
    double x;
    printf("  Please enter the monthly income amount :");
    scanf("%lf", &x);
    printf("  Personal income tax payable ：%9.2f\n", s(x));

    return 0;
}

result ：

// Solve the square root inequality 
int main()
{
    
    long i, m; double n, s, s1;
    printf("  Please enter a positive number n (n>3)：");
    scanf ("%lf", &n) ; // Enter any positive number  
    m=0;
    while (1)
    {
     
	 m++;
     s=0; 
     for (i=m; i<=2*m; i++) 
     s=s+sqrt (i) ; // Calculate and  s 
     if (s >= n) break;
      else s1=s; // Provide basis for the following notes 
    }
    printf("  The solution of the inequality is  m >= %ld\n",m);
    printf(" notes ： When m = %ld when , s = %.2f;  When  m = %ld when , s = %.2f\n", m-1, s1, m, s);
    return 0;
}

result ：

// Simplify solving square root inequality  
int  main()
{
    
    long m;
     double n, s, s1;
     printf("  Please add a positive number n (n > 3)：");
    scanf ("%lf", &n) ;// Enter any positive number  
     m = 1;
     s = 1.0+ sqrt (2);
     do
     {
    
         m++;
         s1 = s;
         s = s - sqrt( m - 1) + sqrt(2 * m- 1) + sqrt (2*m);
     }
     while(s < n);
    printf("  The solution of the inequality is  m >= %ld\n",m);
    printf(" notes ： When m = %ld when , s = %.2f;  When  m = %ld when , s = %.2f\n", m-1, s1, m, s);
    return 0;
}

result ：

// Find demodulation and series inequality  
 int main()
 {
     
    long c, d, m;
    double x, y, s;
    printf("  Please enter a positive number  x,y (2<x<y)： ");
    scanf ("%lf,%lf", &x, &y); 
       m=0;
	   s=0; 
	   while (s <= x) // Cyclic summation exploration m The lower bound of c 
         s = s + 1.0 / (++m);
       c = m;
        do
        s = s + 1.0/ (++m) ;
        while (s < y);// Cyclic summation exploration m The upper bound of d
        d = m-1;
        printf("  The solution satisfying the inequality is ：%1d ≤ m ≤ %1d \n", c, d);
        return 0;
 }

result ：

// Solving inequalities ：d<1+1/2-1/3+1/4+1/5-1/6+.. Scholar 1/n 
int main()
{
     
    long n, k;
    double d,s;
     printf("  Please enter a positive number  d：");
     scanf ("%lf", &d) ;
      printf(" %lf <1+1/2-1/3+1/4+1/5-1/6+..+-1/n  Solution ：\n",d);
       n=3;
       s=3.0/2; 
       while (1)
        {
     
			s = s - 1.0 / n + 1.0 / (n+1) + 1.0 / (n+2);
        	if (s > d) break; 
          	n = n + 3;
        }
           printf(" n = %ld \n", n + 2);
           k = n + 2;
           while(1)
           {
    
                if ((s = s - 1.0 / (++k)) > d) break;
                 if ((s = s + 1.0 / (++k)) > d) break;
                  s = s + 1.0 / (++k);
                
                   printf(" n = %ld \n", k) ; // Discrete solution k
           }
            printf(" n >= %ld \n", k);
            return 0;
}

result ：

 // Solving inequalities ：d<1+1/2-1/3+1/4+1/5-1/6+.. Scholar 1/n 
int main()
{
     
    long n, k;
    double d,s;
     printf("  Please enter a positive number  d：");
     scanf ("%lf", &d) ;
      printf(" %lf <1+1/2-1/3+1/4+1/5-1/6+..+-1/n  Solution ：\n",d);
       n=1;
       s=0; 
       while (1)
        {
     
			s = s + 1.0 / n + 1.0 / (n+1) - 1.0 / (n+2);
        	if (s > d) break; 
          	n = n + 3;
        }
           printf(" n >= %ld \n", n + 1);
           for(s = 0, k =1; k <= n; k++)
           {
    
           	
           		if(k  % 3 > 0) s = s + 1.0 / k;
           		else s = s- 1.0/ k;
           		if(s > d)  printf(" n = %ld \n", k);
		   }
		   
           
            return 0;
}

result ：