C language loop structure and time function usage examples tutorial

This paper illustrates the C language loop structure and the use of time function, which is a good reference for the learning of C language. Share with you for your reference. The details are as follows:

The complete example code is as follows:

#include <stdio.h>       
#include <ctype.h>       
#include <stdbool.h>      
#include <time.h>        
#include <stdlib.h>       

int main(void)
{
    char nextGame = 'Y';      
    bool correct = false;      
    int counter = 0;        
    int seq_len = 0;        
    int input_num = 0;       
    time_t seed = 0;        
    //int i = 0;            

    clock_t start_clock = 0;    
    int time_taken = 0;       

    printf("Here is a simon game for training memory ability .n");
    printf("nThe screen will show a number sequence for 1 second , ");
    printf("then the sequence will disappear. You are suggested to "
        "input the same sequence to pass the game.n");
    printf("nNotice this: each digit is seperated by a space. n");
    printf("nNow press Enter to play .. Good luck !n");
    scanf("%c",&nextGame); //Waiting for user's input

    do
    {
        correct = true ;
        counter = 0 ;  
        seq_len = 2 ;  
        time_taken = clock();

        while(correct)
        {
            
            seq_len += (counter++ % 3 == 0);
            //if "==" expression is true,returns 1; else returns 0

            
            seed = time(NULL);

            
            srand((unsigned int)seed);
            //initialize the seed for rand() function
            for(int i=0; i<seq_len; i++)
                printf("%d ",rand() % 10);
                //Output a random digit and a space

            
            start_clock = clock() ;
            //returns start clock time,clock() is a timer
            for(;clock() - start_clock < CLOCKS_PER_SEC;) ;
            //CLOCKS_PER_SEC is a const defined in time.h

            
            printf("r");
            //control char "r" : locator back to beginning of the line
            for(int i=0; i<seq_len; i++)
                printf(" ");
                //two spaces to overwrite the sequence
            printf("r");

            
            srand((unsigned int)seed);   //Restart the random sequence
            for(int i=0; i<seq_len; i++)
            {
                scanf("%d",&input_num); //Read an input number
                if(input_num != rand() % 10 )
                {
                    correct = false ;
                    break;
                }
            }

            printf("%sn",correct ? "Correct !" : "Wrong !");
        }

        
        time_taken=(clock() - time_taken) / CLOCKS_PER_SEC ;

        
        printf("nnYour score is %d", --counter * 100 / time_taken);

        fflush(stdin); //Empty the input buffer

        printf("nDo you want to play again (y/n)? ");
        scanf("%c",&nextGame);
    } while(tolower(nextGame) == 'y');
    return 0;
}

This example is from a foreign website, as a digital game, interested readers can debug the run, understand the code principle, deepen the understanding of C language loop domain time function.