This code just do not work,please tell me why?

Question

#include<stdio.h>

int main()
{
  int n,i,j;
  
  printf("How many rows you want in your pyramid?\n");
  
  scanf("%d",&n);
  
  for(i = 1; i <= n; i++)
     {
        for(j = 1; j >=2*n-1; j++)
        {
            if(j >= n-(i-1) && j <= n+(i-1))
            {
                printf("*");
                
            }
            else
            {
            printf(" ");
                
            }
       }
       printf("\n");
     }
     return 0;
       
}

Answer 1

for(j = 1; j <=2*n-1; j++)

Your code incorrectly checked if j >= 2 * n - 1, instead of the correct (above) less or equal state.

Answer 2

try to put braces after 2*(n-1) like this