为什么time.sleep（）延迟在嵌套的while循环内无法正常工作？

Question

Can someone explain why the following code (to print multiplication table) is not working as intended ?

import time
n = int(input("Enter number of multiples: "))
k = int(input("Enter number of tables: "))
c = 1
m = 1 #multiple
while m <= n:
    while c <= k:
        print("%4d" % (c*m), end='')
        c+=1
        time.sleep(1) #slower behaviour
    m+=1
    c=1
    print("")

What's strange about this is that instead of printing single horizontal elements in intervals of one second, it is printing the entire row at once in an interval of 'k' seconds.

In fact, code written in C showed the same behavior.

#include<stdio.h>
#include<unistd.h>
void main(){
    int n,k,c=1,m=1;
    printf("Enter number of Multiples: ");
    scanf("%d",&n);
    printf("Enter number of tables: ");
    scanf("%d",&k);
    while(m<=n){
        while(c<=k){
            printf("%4d",(c*m));
            c+=1;
            //sleep(1); //slower here
        }
        m+=1;
        c=1;
        sleep(1); //faster here
        printf("\n");
    }
}

That is, instead of printing an element and waiting for a second, it printed entire row at once in intervals of 'k' second(s).

Answer 1

You told print to skip the newline but terminal output is line buffered. You need to flush the data.

print("%4d" % (c*m), end='', flush=True)