C language applet -- common classic practice questions

Share 5 simple C language small programs, now you, do you still remember the C language you studied hard at the time, the classic C language questions, recall it

[Program 1] Question: With 1, 2, 3, and 4 numbers, how many different three-digit numbers can be formed without repeating numbers?How much are they?

1. Program analysis: The numbers that can be filled in the hundreds, tens, and ones are 1, 2, 3, and 4.Make up all the permutations and then remove the permutations that do not meet the conditions.

2. Program source code:

#include int main(){int i,j,k;printf("\n");for(i=1;i<5;i++) /*The following is a triple loop*/for(j=1;j<5;j++)for (k=1;k<5;k++){if (i!=k&&i!=j&&j!=k) /*make sure i,j,k are different from each other*/printf("%d,%d,%d\n",i,j,k);}}

【Program 2】
Question: Enter a certain day, a certain month, a certain year, and determine the day of the year?
1. Program analysis: Take March 5th as an example, you should add up the first two months, and then add 5 days, which is the first day of the year, special cases, leap years and the input month is greater than 3need to consider an extra day.
2. Program source code:

#include int main(){int day,month,year,sum,leap;printf("\nplease input year,month,day\n");scanf("%d,%d,%d",&year,&month,&day);switch(month) /*First calculate the total number of days in the month before a certain month*/{case 1:sum=0;break;case 2:sum=31;break;case 3:sum=59;break;case 4:sum=90;break;case 5:sum=120;break;case 6:sum=151;break;case 7:sum=181;break;case 8:sum=212;break;case 9:sum=243;break;case 10:sum=273;break;case 11:sum=304;break;case 12:sum=334;break;default:printf("data error");break;}sum=sum+day; /*Add the number of days in a day*/if(year%400==0||(year%4==0&&year%100!=0)) /*Determine whether it is a leap year*/leap=1;elseleap=0;if(leap==1&&month>2) /*If it is a leap year and the month is greater than 2, add one day to the total number of days*/sum++;printf("It is the %dth day.",sum);}

【Program 3】
Title: Input three integers x, y, z, please output the three numbers from small to large.
1. Program analysis: We find a way to put the smallest number on x, first compare x with y, if x>y, exchange the values ​​of x and y, and then compare x and z, if x>z, swap the values ​​of x and z to minimize x.
2. Program source code:

#include int main(){int x,y,z,t;scanf("%d%d%d",&x,&y,&z);if (x>y){t=x;x=y;y=t;} /*Swap the values ​​of x,y*/if(x>z){t=z;z=x;x=t;} /*Swap the values ​​of x,z*/if(y>z){t=y;y=z;z=t;} /*Swap the values ​​of z,y*/printf("small to big: %d %d %d\n",x,y,z);}

【Program 4】
Title: Output 9*9 formula.
1. Program analysis: consider row and column, a total of 9 rows and 9 columns, i controls the row, j controls the column.
2. Program source code:

#include int main(){int i,j,result;printf("\n");for (i=1;i<10;i++){for(j=1;j

【Program 5】
Title: Print out all the "daffodils number", the so-called "daffodil number" refers to a three-digit number, and the sum of the cubes of the digits is equal to the number itself.For example: 153 is a "daffodil number", because 153=1 cube + 5 cube + 3 cube.
1. Program analysis: use the for loop to control 100-999 numbers, each number is decomposed into units, tens, and hundreds.
2. Program source code:

#include main(){int i,j,k,n;printf("'water flower'number is:");for(n=100;n<1000;n++){i=n/100;/*Decompose to the hundreds place*/j=n/10%10;/*decompose to ten digits*/k=n%10;/*Decompose out the one digit*/if(i*100+j*10+k==i*i*i+j*j*j+k*k*k)printf("%-5d",n);}}

And that's it for today, everyone remember to like and favorite, share and forward, and pay attention to little brother!Finally, if you want to learn or are learning C/C++ programming, you can join Editor’s Programming Learning C/C++ Penguin Circle