# Brother Peng took me to brush good questions · programming practice · II

Hello, everyone. I'm safe and sound.

catalogue

1. Judgment letter

2. Character Christmas tree

3.ASCII code

4. Input and output of birth date

5.2 calculation to the nth power of

6. Input and exchange output according to format

7. Character to ASCII

8. Calculate the value of the expression

9. Calculate division with remainder

10. Calculate body mass index

11. Calculate the perimeter and area of the triangle

12. Calculate the volume of the sphere

Conclusion: meet Enron meet you, not negative code, not negative Qing!

[preface]

The title is relatively simple, 130 to the title, two brush, because many solutions written before are too cumbersome, so it takes a few days to go over it again.

# 1. Judgment letter

Original title link: Judgment letter_ Niuke Tiba_ Niuke network

Title Description:

Code execution:

Code 1:

```#include<stdio.h>
int main()
{
int ch = 0;
//Multi group input
while((ch=getchar())!=EOF)
{

if(ch>='A' && ch<='Z' || ch>='a' && ch<='z')
{
printf("YES\n");
}
else
{
printf("NO\n");
}
getchar();//Be sure to clear the buffer

}

return 0;
}```

Code 2:

```//isplpha - is a library function designed to determine whether a character is a letter
//If it is a letter, it returns a value other than 0, and if it is not a letter, it returns 0
//Header file #include < ctype. Required h>
#include<stdio.h>
#include<ctype.h>

int main()
{
int ch = 0;
//Multi group input
while((ch = getchar())!=EOF)
{
//Judge and output
if(isalpha(ch))
{
printf("YES\n");
}
else
{
printf("NO\n");
}
getchar();//Clear buffer \ n
}
return 0;
}```

# 2. Character Christmas tree

Original title link: Character Christmas tree_ Niuke Tiba_ Niuke network

Title Description:

Example:

```Input: 1
Output:
1
1 1
1 1 1
1 1 1 1
1 1 1 1 1```

Code execution:

```#include<stdio.h>

int main()
{
char ch = 0;
ch = getchar();
int i = 0;
//Print one line per cycle
//Each line consists of two parts: spaces and characters
for (i = 0; i < 5; i++)
{
//Print spaces
int j = 0;
for (j = 0; j < 5 - 1 - i; j++)
{
printf(" ");
}
//Print character
for (j = 0; j <= i; j++)
{
printf("%c ", ch);
}
printf("\n");
}
return 0;
}```

# 3.ASCII code

Original title link: ASCII code_ Niuke Tiba_ Niuke network

Title Description:

Code execution:

```#include<stdio.h>
int main()
{
char arr[] = {73,32,99,97,110,32,100,111,32,105,116,33};
//arr is an array that is accessed using subscripts
//Calculate the number of array elements
int sz = sizeof(arr) / sizeof(arr[0]);
int i = 0;
for(i = 0; i < sz; i++)
{
printf("%c", arr[i]);
}
return 0;
}```

# 4. Input and output of birth date

Original title link: Date of birth input / output_ Niuke Tiba_ Niuke network

[knocking on the blackboard]: pay attention to the input and output format.

Title Description:

Example:

```Input: 20130225
Output:
year=2013
month=02
date=25```

Note:

Through the%m format control of scanf function, you can specify the input field width and the input data field width (number of columns), and intercept the required data according to this width; Through the% 0 format controller of printf function, specify the empty position not used on the left when outputting the value, and fill in 0 automatically.

Code execution:

```#include<stdio.h>

int main()
{
int year = 0;
int month = 0;
int date = 0;
//Enter in format
scanf("%4d%2d%2d", &year, &month, &date);
//output
printf("year=%4d\n", year);
printf("month=%02d\n", month);
printf("date=%02d\n", date);
return 0;
}```

# 5.2 calculation to the nth power of

Original title link: Calculation to the nth power of 2_ Niuke Tiba_ Niuke network

Title Description:

If you want to learn more, you can take a look at my article:

Chapter 1 of the Blue Bridge Cup algorithm competition series -- the ingenious technique of bit operation and its practical combat_ Enron carefree blog - CSDN blog [statement]: in the next two months, the blogger will continue to launch two series of blog articles about zero foundation C language and Blue Bridge Cup algorithm competition. Readers are welcome to express their ideas and look forward to your comments.https://blog.csdn.net/weixin_57544072/article/details/120798996

Code execution:

```#include<stdio.h>

int main()
{
int n = 0;
//Multi group input
while(scanf("%d", &n)!=EOF)
{
printf("%d\n", 1<<n);
}

return 0;
}```

# 6. Input and exchange output according to format

Original title link: Input and exchange output in format_ Niuke Tiba_ Niuke network

Title Description:

Example:

```Input: a=1,b=2
Output: a=2,b=1```

Code execution:

```#include<stdio.h>

int main()
{
int a = 0;
int b = 0;
int c = 0;
scanf("a=%d,b=%d", &a, &b);
//exchange
//Imagine a bottle of soy sauce and a bottle of vinegar, and then exchange an empty bottle
c = a;
a = b;
b = c;
//output
printf("a=%d,b=%d\n", a, b);
return 0;
}```

Add a abnormal written test question:

You cannot create a temporary variable (the third variable) to exchange two numbers:

a = a + b;

b = a - b;

a = a - b;

This solves the problem, but there are some disadvantages. If a and B are large, it may lead to overflow, so another method is to use XOR

Method 2: XOR method

a = a ^ b;

b = a ^ b;

a = a ^ b;

In this way, the exchange is completed, but in practical application, it is customary to define the third variable to realize the exchange of two numbers, because the readability of the above code is not high!

# 7. Character to ASCII

Original title link: Character to ASCII_ Niuke Tiba_ Niuke network

Title Description:

Example:

```Input: a
Output: 97```

Code execution:

```#include<stdio.h>
int main()
{
char ch = 0;
ch = getchar();
printf("%d\n",ch);
return 0;
}```

# 8. Calculate the value of the expression

Original title link: Evaluate the value of the expression_ Niuke Tiba_ Niuke network

Title Description:

Code execution:

```#include<stdio.h>
int main()
{
int a = 40;
int c = 212;
printf("%d\n", (-8+22)*a - 10 + c / 2);
return 0;
}```

# 9. Calculate division with remainder

Original title link: Calculating division with remainder_ Niuke Tiba_ Niuke network

Title Description:

Example:

```Input: 15 2
Output: 7 1```

Code execution:

```#include<stdio.h>

int main()
{
int a = 0;
int b = 0;
scanf("%d %d", &a, &b);
// /The division operator gets the quotient
// %The remainder (modulo) operator gets the remainder
int c = a/ b;
int d = a % b;
printf("%d %d\n", c, d);
return 0;
}```

# 10. Calculate body mass index

Original title link: Calculate body mass index_ Niuke Tiba_ Niuke network

Title Description:

Example:

```Input: 70 170
Output: 24.22```

Code execution:

```#include<stdio.h>
int main()
{
int weight = 0;
int height = 0;
double bmi = 0.0;
//input
scanf("%d %d", &weight, &height);
//Calculate BMI
//The reason for dividing by 100.0 is that both sides of the division sign are integers. To get a decimal, you must ensure that one on both sides is a floating point number
bmi = weight / ((height / 100.0) * (height / 100.0));
//output
printf("%.2lf\n", bmi);
return 0;
}```

# 11. Calculate the perimeter and area of the triangle

Original title link: Calculate the perimeter and area of the triangle_ Niuke Tiba_ Niuke network

Title Description:

Example:

```Input: 3
Output: circumference=9.00 area=3.90```

Note: given the three sides of the triangle, let's calculate the area of the triangle, then we need to use Helen's formula, and the problem will be solved easily.

Code execution:

```#include<stdio.h>
#include<math.h>

int main()
{
double a = 0.0;
double b = 0.0;
double c = 0.0;

double circumference = 0.0;//Perimeter
double area = 0.0;//the measure of area
//input
scanf("%lf %lf %lf", &a,&b,&c);
//calculation
circumference = a + b + c;
double p = (a + b + c) / 2;
area = sqrt(p * (p - a) * (p - b) * (p - c));
printf("circumference=%.2lf area=%.2lf\n",circumference, area);
return 0;
}```

# 12. Calculate the volume of the sphere

Original title link: Calculate the volume of the sphere_ Niuke Tiba_ Niuke network

Title Description:

Code execution:

```#include<stdio.h>
#include<math.h>
#include<math.h>
#define PI 3.1415926
int main()
{
double r = 0.0;
double v = 0.0;
//input
scanf("%lf", &r);
//calculation
v = 4.0 / 3 * PI * pow(r, 3);
//output
printf("%.3lf\n", v);
return 0;
}```

# Conclusion: meet Enron meet you, not negative code, not negative Qing!

Please, let's have a three company.

Keywords: C

Added by vikaspa on Tue, 11 Jan 2022 03:44:18 +0200