How to port JS code to C, what am I doing wrong?

Question

Programming

Is it possible to transfer this from JS to C?
for (var line = "#"; line.length < 7; line += "#") {
console.log(line);
Like
for(char line="#"; line.length<7; line+="#"){
printf("%d",line);
}
You need to line up something like:
#
##
###
####
#####
######
#######

Answer 1

In pure C, there are no dynamic strings, only numeric variables, pointers (references), structures, and fixed size arrays. The closest to JS code, but also the most crooked, will be the following code:

char line[8];
*line = 0;
for(strcat(line, "#"); strlen(line) < 7; strcat(line, "#"))
    puts(line);

Answer 2

char line = '#';
for (int i=1; i<=7; i++)
{
  for (int j=1; j<=i; j++)
    printf("%d", line); //Напечатать решетку
  printf("%d", "\n"); //Перевести на нов. строку
}