C language actual combat guessing game

Preface

The knowledge involved

1.if Branch statement 、do、while、for Loop statement
2. The generation of random numbers and the change of seeds
3. Array setting and acquisition

Guessing game setup steps

Game design

Conditional branch （ Non playable version ）

In order to realize the final guessing game , Let's start with a simple guessing game . Design a program , It is used to display the comparison result between the value entered by the player and the value set in the computer .

#include<stdio.h>
int main()
{
    
	int a;// Read number 
	int ans;// The target number set by the crude version 
	ans = 30;// Set the number to guess as 30
	printf(" Please enter an integer you guessed ：");
	scanf("%d", &a);
	if (a > ans)
	{
    
		printf(" You guessed big ！\n");
	}
	else if (a < ans)
	{
    
		printf(" You guess it's small ！\n");
	}
	else
	{
    
		printf(" You guessed it ！\n");
	}
	return 0;
}

The above procedure uses if Branch statement , Unfamiliar friends can review the relevant sentences .

Repeat the cycle （ Rough version ）

Although the above code can show the relationship between the result guessed by the player and the set number , But I can only play once , Every time you guess, the program will end , If you want to guess the second time, you need to reopen the program , This is too boring . So we need to use do Statement to make the program repeatable , Until the player guesses right .

#include<stdio.h>
int main()
{
    
	int a;
	int ans;
	ans = 30;
	do
	{
    
		printf(" Please enter an integer you guessed ：");
		scanf("%d", &a);
		if (a > ans)
		{
    
			printf(" You guessed big ！\n");
		}
		else if (a < ans)
		{
    
			printf(" You guess it's small ！\n");
		}
	} while (a != ans);
	printf(" You guessed it ！");
	return 0;
}

The above procedure uses do Loop statement , Unfamiliar friends can review the relevant sentences .

Of course , Our statements that can realize the requirement of repeating loops are not only do sentence , Let's use while Statement to achieve the above requirements .

#include<stdio.h>
int main()
{
    
	int a;
	int ans;
	ans = 30;
	while (1)
	{
    
		printf(" Please enter an integer you guessed ：");
		scanf("%d", &a);
		if (a > ans)
		{
    
			printf(" You guessed big ！\n");
		}
		else if (a < ans)
		{
    
			printf(" You guess it's small ！\n");
		}
		else
		{
    
			break;
		}
	}
		printf(" You guessed it ！");
	return 0;
}

The above procedure uses while sentence , Unfamiliar friends can review the relevant sentences .
while The control expression of the statement is 1,1 For true, the cycle will continue , But when we guessed the right number , Then it will carry out break sentence ,break The function of the statement is to jump out of the loop , So we use while Statement completes the requirements of the loop .

Here we will distinguish the following do Statement and while The specific differences between sentences ：
do The statement is to loop first and then judge , in any case , The loop body will be run once .
while Statement and for Statements are judged first and then looped , The loop body may not be executed once .

Digital randomised （ Playable version ）

Although the above code can be played , But when the player answers correctly once , You can guess the answer at once , In order to make the answer of the game different every time , Improve the playability of the game , We should make every answer random . Now let's write several groups of code to generate random numbers .

#include<stdio.h>
#include<stdlib.h>
int main()
{
    
	int retry;
	printf(" Can generate 0~%d The random number .\n", RAND_MAX);
	do
	{
    
		printf("\n Generated a random number %d\n", rand());
		printf(" Whether to run again ？ no ···0  yes ···1\n");
		scanf("%d", &retry);
	} while (retry == 1);
	return 0;
}

The above procedure uses rand sentence , Unfamiliar friends can review the relevant sentences .

Introduce the following rand function ：

Use rand The function needs to reference the header file ：#include<stdlib.h>
rand The function of ：rand Function returns a range from 0 To RAND_MAX Of pseudo-random integers .
rand The return value of ： Returns the generated pseudo-random number integer

Although the above program can generate a group of random numbers , But when we run it many times, we will find . The random number sequence generated at each run time is the same , such rand The generated values are not really random , So we need to improve it .

#include<stdio.h>
#include<stdlib.h>
#include<time.h>
int main()
{
    
	int retry;/* Once again */
	srand(time(NULL));/* Set the random number seed according to the current time */
	printf(" Can generate 0~%d The random number .\n", RAND_MAX);
	do
	{
    
		printf("\n Generated a random number %d\n", rand());
		printf(" Whether to run again ？ no ···0  yes ···1\n");
		scanf("%d", &retry);
	} while (retry == 1);
	return 0;
}

The above procedure uses srand sentence , Unfamiliar friends can review the relevant sentences .
Use srand Set the value of seed to the running time of the program , In this way, we can ensure that the seeds are different each time, and naturally the random number sequence generated each time will not be the same ！

Introduce the following srand function ：

Use srand The function needs to reference the header file ：#include<time.h>
srand The function of ：srand The function sets the starting point for generating a series of pseudo-random integers , In short , to rand Function to set a seed , Used to generate subsequent random number sequences . If not applicable srand function , that rand The function will set the seed value to 1.

Although the above code can meet the requirement of random number generation , however ,rand The value generated by the function is ：0~RAND_MAX (32767) , The random value we need cannot be completely within the range set by ourselves , So we need further improvement , Set the range of the following generation numbers , This can make the game more playable .

#include<stdio.h>
#include<stdlib.h>
#include<time.h>
int main()
{
    
	int a;/* The value of the input */
	int ans;/* random number */
	srand(time(NULL));/* Set time seed */
	ans = rand() % 100;/* Divide the generated random number by 100 Assign the remainder of to ans*/
	puts(" Please enter a 0~99 The number of .");
	do
	{
    
		printf(" Please enter an integer you guessed ：");
		scanf("%d", &a);
		if (a > ans)
		{
    
			printf(" You guessed big ！\n");
		}
		else if (a < ans)
		{
    
			printf(" You guess it's small ！\n");
		}
	} while (a != ans);
	printf(" You guessed it ！");
	return 0;
}

We will rand Divide the random number generated by the function by 100 Take the remainder , You can get a group with a range of 0~99 The random number
rand（）% （a+1） Set the range to be greater than or equal to 0 And less than or equal to a Within the scope of
b+rand（）% （a+1） Set the range to be greater than or equal to b And less than or equal to b+a Within the scope of

Restriction times （ The second perfect version ）

In fact, the above code can already have a good game experience , But we can make him more interesting , We can set the limit of input times , Make the game more interesting .

#include<stdio.h>
#include<stdlib.h>
#include<time.h>
#define MAX_STAGE 10 /* The maximum number of entries ！*/
int main()
{
    
	int a;/* The value of the input */
	int ans;/* random number */
	const int max = MAX_STAGE;/* The maximum number of entries */
	int remain = max;
	srand(time(NULL));/* Set time seed */
	ans = rand() % 100;/* Divide the generated random number by 100 Assign the remainder of to ans*/
	puts(" Please enter a 0~99 The number of .");
	do
	{
    
		printf(" You still have %d Second chance , Please enter the integer you guessed ：",remain);
		scanf("%d", &a);
		remain--;
		if (a > ans)
		{
    
			printf(" You guessed big ！\n");
		}
		else if (a < ans)
		{
    
			printf(" You guess it's small ！\n");
		}
	} while (a != ans && remain > 0 );
	if (a != ans)
	{
    
		printf("\n unfortunately , The correct answer is ：%d", ans);
	}
	else
	{
    
		printf(" Correct answer ！\n");
		printf(" You use the %d I guessed right .\n",max-remain);
	}
	return 0;
}

The maximum number of input variables is declared here max It's time to use it const Make the value of the variable impossible to modify , So you don't have to worry about the follow-up reamin– It has been written. max– Without knowing it （ The compiler will report an error ）

When modifying the data declaration ,const Keyword specifies that the object or variable cannot be modified . When following the formal parameter list of a member function ,const Keyword specifies that the function does not modify the called object .

Save input （ Perfect edition ）

The above code is perfect , But if we add the function of saving input records , Will make this game more perfect .

#include<stdio.h>
#include<stdlib.h>
#include<time.h>
#define MAX_STAGE 10 /* The maximum number of entries ！*/
int main()
{
    
	int i;
	int stage = 0;/* Number of times entered */
	int a;/* Value read */
	int ans;/* Target value */
	int num[MAX_STAGE];/* History of values read */
	srand(time(NULL));
	ans = rand() % 100;
	printf(" Please enter a 0~99 The number of \n");
	do
	{
    
		printf(" You still have %d Second chance , Please enter the integer you guessed ：", MAX_STAGE - stage);
		scanf("%d", &a);
		num[stage++] = a;
		if (a > ans)
		{
    
			printf(" You guessed big ！\n");
		}
		else if (a < ans)
		{
    
			printf(" You guess it's small ！\n");
		}
	} while (a != ans && stage < MAX_STAGE);
	if (a != ans)
	{
    
		printf("\n unfortunately , The correct answer is ：%d", ans);
	}
	else
	{
    
		printf(" Correct answer ！\n");
		printf(" You use the %d I guessed right .\n",  stage);
	}
	puts("------ Input record -------");
	for (i = 0; i < stage; i++)
		printf("%2d:%4d %+4d\n", i + 1, num[i], num[i] - ans);
	return 0;
}

In order to save the player's previous records , You need to store it in an array .

summary

Game code

#include<stdio.h>
#include<stdlib.h>
#include<time.h>
#define MAX_STAGE 10 /* The maximum number of entries ！*/
int main()
{
    
	int i;
	int stage = 0;/* Number of times entered */
	int a;/* Value read */
	int ans;/* Target value */
	int num[MAX_STAGE];/* History of values read */
	srand(time(NULL));
	ans = rand() % 100;
	printf(" Please enter a 0~99 The number of \n");
	do
	{
    
		printf(" You still have %d Second chance , Please enter the integer you guessed ：", MAX_STAGE - stage);
		scanf("%d", &a);
		num[stage++] = a;
		if (a > ans)
		{
    
			printf(" You guessed big ！\n");
		}
		else if (a < ans)
		{
    
			printf(" You guess it's small ！\n");
		}
	} while (a != ans && stage < MAX_STAGE);
	if (a != ans)
	{
    
		printf("\n unfortunately , The correct answer is ：%d", ans);
	}
	else
	{
    
		printf(" Correct answer ！\n");
		printf(" You use the %d I guessed right .\n",  stage);
	}
	puts("------ Input record -------");
	for (i = 0; i < stage; i++)
		printf("%2d:%4d %+4d\n", i + 1, num[i], num[i] - ans);
	return 0;
}

Running results

Knowledge summary

Preparation for generating random numbers

Before generating random numbers, you need to set them based on the current time ” seeds “ Value .

#include<stdio.h>
#include<time.h>
#include<stdlib.h>
srand(time (NULL));

In the initial call rand Function is called first srand Function to set the seed , If not called srand function , that rand The seed of the function defaults to 1, The resulting number is not random enough .

Tips for generating random numbers

call rand Function will be generated randomly 0~RAND_MAX The random number ,RAND_MAX Depends on the compiler , Greater than or equal to 32767.
If you need to limit the random number to a certain range , You can do this as follows ：
rand（）% （a+1） Set the range to be greater than or equal to 0 And less than or equal to a Within the scope of .
b+rand（）% （a+1） Set the range to be greater than or equal to b And less than or equal to b+a Within the scope of .

The difference between the three cycles

do The statement is to loop first and then judge , in any case , The loop body will be run once .
while Statement and for Statements are judged first and then looped , The loop body may not be executed once .