Introduction
Help with homework qwq…
I haven’t played with C language for a long time, let me try to see if I can do it.
PS: I’m on Linux, the execution method may be different. If you are on Windows, you need an editor to run it.
For example, Dev C++, VS 2019, etc.
Experiment Eleven
Experiment Eleven
Objective:
- Understand C programming concepts
- Understand C program design framework
Contents:
Input a grade and output its level rating.
This is straightforward. We need to list several grade levels:
In the code, we can use expressions to represent the intervals, for example:
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score >= 80 && score <= 100
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Then we use if() to determine the grade level.
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#include<stdio.h>
int main(){
int score = 85;
if(score >= 80 && score <= 100){
printf("The grade is excellent");
}else if(score >= 60 && score <= 79){
printf("The grade is pass");
}else if(score >= 0 && score < 60){
printf("The grade is fail");
}
}
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Next, we run the program.
Output:
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weepingdogel@WeepingDogel /tmp> make test
cc test.c -o test
weepingdogel@WeepingDogel /tmp> ./test
The grade is excellent⏎
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Then we need to get the user’s input for the grade, like this, using the scanf() function to get the user’s input and assign it to an integer variable score.
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#include<stdio.h>
int main(){
int score;
printf("Enter your grade:");
scanf("%d",&score);
printf("%d",score);
}
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Next, we combine these two pieces of code together.
The complete code is as follows:
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#include<stdio.h>
int main(){
int score;
printf("Enter your grade:");
scanf("%d",&score);
if(score >= 80 && score <= 100){
printf("The grade is excellent");
}else if(score >= 60 && score <= 79){
printf("The grade is pass");
}else if(score >= 0 && score < 60){
printf("The grade is fail");
}
}
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The idea is to first use scanf() function to get the user’s input for the grade, then use if() statements to compare and output the result.
This is the output:
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weepingdogel@WeepingDogel /tmp> make test
cc test.c -o test
weepingdogel@WeepingDogel /tmp> ./test
Enter your grade:99
The grade is excellent⏎
weepingdogel@WeepingDogel /tmp> ./test
Enter your grade:85
The grade is excellent⏎
weepingdogel@WeepingDogel /tmp> ./test
Enter your grade:60
The grade is pass⏎
weepingdogel@WeepingDogel /tmp> ./test
Enter your grade:59
The grade is fail⏎
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Experiment 12
Experiment Purpose:
- Understand C program design ideas
- Understand C program design frameworks
Task content
- Requires writing a program that registers and then logs in, outputting the format shown in the following figure:
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--------------------------------------
Registration Interface
Please enter your registration username: Ly
Please enter your registration password: 123
Congratulations! Registration successful!
--------------------------------------
--------------------------------------
Login Interface
Please enter your login username: Ly
Please enter your login password: 123
Login successful!
--------------------------------------
--------------------------------------
Login Interface
Please enter your login username: Ly
Please enter your login password: 1234
Login failed!
--------------------------------------
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- Define 4 variables to save the registered username, password and login username, password respectively.
- Use if…else statement to complete the judgment of the username and password.
To put it simply… it uses scanf() to get input, assigns the values to variables, and then performs the judgment…
Pft! Alright, here’s the code, no explanation needed…
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#include<stdio.h>
#include<string.h>
int main(){
/* Define 4 variables to save the registered username,
password and login username, password respectively */
char username_sign[40];
char password_sign[16];
char username_login[40];
char password_login[16];
/* Define 4 variables to save the registered username,
password and login username, password respectively */
printf("--------------------------------------\n Registration Interface\n");
printf("Please enter your registration username:");
scanf("%s", username_sign);
printf("Please enter your registration password:");
scanf("%s", password_sign);
printf("Congratulations! Registration successful!");
printf("\n--------------------------------------");
/* Use scanf() to get input */
printf("\n\n--------------------------------------\n Login Interface\n");
printf("Please enter your login username:");
scanf("%s",username_login);
printf("Please enter your login password:");
scanf("%s",password_login);
/* Use if...else statement to complete the judgment of the username and password */
/* Uses the strcmp() function here */
if(strcmp(username_login,username_sign) == 0 && strcmp(password_login,password_sign) == 0){
printf("Login successful!");
}else{
printf("Login failed!");
}
printf("\n--------------------------------------");
}
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However, it’s worth noting that this string comparison method is slightly different. It requires using the strcmp() function, something like this.
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if(strcmp(username_login,username_sign) == 0 && strcmp(password_login,password_sign) == 0){
printf("Login successful!");
}else{
printf("Login failed!");
}
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It seems to calculate a numerical value, which equals 0 if the two strings are the same. That’s roughly how it works.
Let’s take a look at the output…
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weepingdogel@WeepingDogel /tmp> make test2
cc test2.c -o test2
weepingdogel@WeepingDogel /tmp> ./test2
--------------------------------------
Registration Interface
Please enter your registration username:Ly
Please enter your registration password:123
Congratulations! Registration successful!
--------------------------------------
--------------------------------------
Login Interface
Please enter your login username:Ly
Please enter your login password:123
Login successful!
--------------------------------------⏎
weepingdogel@WeepingDogel /tmp> ./test2
--------------------------------------
Registration Interface
Please enter your registration username:Ly
Please enter your registration password:123
Congratulations! Registration successful!
--------------------------------------
--------------------------------------
Login Interface
Please enter your login username:Ly
Please enter your login password:1234
Login failed!
--------------------------------------⏎
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And that’s it!
Actually, there are still some details that I might overlook due to carelessness, so I can’t say “Is that it? Is that all?”
But relatively speaking, it’s still quite simple… yeah…
