Cant get a Diamond Shape in C right - c

Question

I'm doing a c exercise to do a diamond shape with '#' using a funcion.
My code :
#include <stdio.h>
//Declare function
void losangle(int n);
//main
int main(void){
int n;
do {
printf("Altura do triangulo: ");
scanf("%d", &n );
} while( n % 2 == 0);
losangle(n);}
//function
void losangle(int n){
int i, hashtag, spaces, j, spaces1, hashtag1;
//triangle
for(i = 0; i < n; i++){
for(spaces = 0; spaces < (n-i); spaces++){
printf(" ");}
for(hashtag = 0; hashtag < (i+1);hashtag++){
printf("# ");}
printf("\n");}
//inverted triangle
for(j = 0; j < (n - 1); j++){
for(spaces1 = 0; spaces1 < (j+2); spaces1++){
printf(" ");}
//not working !!!
for(hashtag1 = (n-1); hashtag1 > 0; hashtag1--){
printf("# ");}
printf("\n");
}}
The output is this :
Losangle: 5
#
# #
# # #
# # # #
# # # # #
# # # #
# # # #
# # # #
# # # #
What is making the '#' not decrementing in the bottom part ? Is this line wrong (for(hashtag1 = (n-1); hashtag1 > 0; hashtag1--)) ?? Btw i also accept tips to improve the code efficiency.

Answer 1

Issue:
The inverted triangle for loop iterates from n-1 to 0 every time, regardless of j's value.
Solution:
Iterating between n-1 to j will cause the number of hash symbols to decrease every iteration.
Change this line:
for(hashtag1 = (n-1); hashtag1 > 0; hashtag1--){
to
for(hashtag1 = (n-1); hashtag1 > j; hashtag1--){

Answer 2

Milestone 1
What's the high level logic of the program?
void getInutAndDrawDiamond()
int getTriangleHeight();
void drawDiamond(int height);
int main()
{
getInutAndDrawDiamond();
return 0;
}
void getInutAndDrawDiamond()
{
int height = getTriangleHeight();
drawDiamond(height);
}
with dummy implementations of getTriangleHeight and drawDiamond.
int getTriangleHeight()
{
return 0;
}
void drawDiamond(int height)
{
}
Milestone 2
Add a proper implementation of getTriangleHeight.
int getTriangleHeight()
{
int height;
int c;
char const* prompt = "Enter the height of the triangle: ";
printf("%s", prompt);
while ( scanf("%d", &height) != 1 )
{
// Error reading the input.
// Ignore rest of the line
while ( (c = fgetc(stdin)) != '\n' && c != EOF );
// If EOF is reached, exit.
if ( c == EOF )
{
exit(EXIT_FAILURE);
}
// Try reading again.
printf("%s", prompt);
}
return height;
}
Milestone 3
Add the next level implementation of drawDiamond, using couple of helper functions that have dummy implementations.
void drawUpperHalfOfDiamond(int height);
void drawLowerHalfOfDiamond(int height);
void drawDiamond(int height)
{
drawUpperHalfOfDiamond(height);
drawLowerHalfOfDiamond(height);
}
void drawUpperHalfOfDiamond(int height)
{
}
void drawLowerHalfOfDiamond(int height)
{
}
Milestone 4
Add the next level implementation of drawUpperHalfOfDiamond and drawLowerHalfOfDiamond, using dummy implementations of couple of helper functions.
void drawUpperHalfRowOfDiamond(int row);
void drawLowerHalfRowOfDiamond(int row);
void drawUpperHalfOfDiamond(int height)
{
for (int row = 0; row < height; ++row )
{
drawUpperHalfRowOfDiamond(row);
}
}
void drawLowerHalfOfDiamond(int height)
{
for (int row = 0; row < height; ++row )
{
drawLowerHalfRowOfDiamond(row);
}
}
void drawUpperHalfRowOfDiamond(int row)
{
}
void drawLowerHalfRowOfDiamond(int row);
{
}
Milestone 5
Add the next level implementation of drawUpperHalfRowOfDiamond and drawLowerHalfRowOfDiamond, using dummy implementations of a few helper functions.
int getNumberOfColumsForUpperHalfRow(int row);
void drawUpperHalfCell(int row, int col);
int getNumberOfColumsForLowerHalfRow(int row);
void drawLowerHalfCell(int row, int col);
void drawUpperHalfRowOfDiamond(int row)
{
int cols = getNumberOfColumsForUpperHalfRow(row);
for (int col = 0; col < cols; ++col )
{
drawUpperHalfCell(row, col);
}
}
void drawLowerHalfRowOfDiamond(int row)
{
int cols = getNumberOfColumsForLowerHalfRow(row);
for (int col = 0; col < cols; ++col )
{
drawLowerHalfCell(row, col);
}
}
int getNumberOfColumsForUpperHalfRow(int row)
{
return 0;
}
void drawUpperHalfCell(int row, int col)
{
}
int getNumberOfColumsForLowerHalfRow(int row)
{
return 0;
}
void drawLowerHalfCell(int row, int col)
{
}
Milestone 5
Add proper implementations of the last four functions -- left as an exercise to the reader.
Complete program
#include <stdio.h>
#include <stdlib.h>
void getInutAndDrawDiamond();
int getTriangleHeight();
void drawDiamond(int height);
void drawUpperHalfOfDiamond(int height);
void drawLowerHalfOfDiamond(int height);
void drawUpperHalfRowOfDiamond(int row);
void drawLowerHalfRowOfDiamond(int row);
int getNumberOfColumsForUpperHalfRow(int row);
void drawUpperHalfCell(int row, int col);
int getNumberOfColumsForLowerHalfRow(int row);
void drawLowerHalfCell(int row, int col);
int main()
{
getInutAndDrawDiamond();
return 0;
}
void getInutAndDrawDiamond()
{
int height = getTriangleHeight();
drawDiamond(height);
}
int getTriangleHeight()
{
int height;
int c;
char const* prompt = "Enter the height of the triangle: ";
printf("%s", prompt);
while ( scanf("%d", &height) != 1 )
{
// Error reading the input.
// Ignore rest of the line
while ( (c = fgetc(stdin)) != '\n' && c != EOF );
// If EOF is reached, exit.
if ( c == EOF )
{
exit(EXIT_FAILURE);
}
// Try reading again.
printf("%s", prompt);
}
return height;
}
void drawDiamond(int height)
{
drawUpperHalfOfDiamond(height);
drawLowerHalfOfDiamond(height);
}
void drawUpperHalfOfDiamond(int height)
{
for (int row = 0; row < height; ++row )
{
drawUpperHalfRowOfDiamond(row);
}
}
void drawLowerHalfOfDiamond(int height)
{
for (int row = 0; row < height; ++row )
{
drawLowerHalfRowOfDiamond(row);
}
}
void drawUpperHalfRowOfDiamond(int row)
{
int cols = getNumberOfColumsForUpperHalfRow(row);
for (int col = 0; col < cols; ++col )
{
drawUpperHalfCell(row, col);
}
}
void drawLowerHalfRowOfDiamond(int row)
{
int cols = getNumberOfColumsForLowerHalfRow(row);
for (int col = 0; col < cols; ++col )
{
drawLowerHalfCell(row, col);
}
}
int getNumberOfColumsForUpperHalfRow(int row)
{
// TODO a proper implementation
return 0;
}
void drawUpperHalfCell(int row, int col)
{
// TODO a proper implementation
}
int getNumberOfColumsForLowerHalfRow(int row)
{
// TODO a proper implementation
return 0;
}
void drawLowerHalfCell(int row, int col)
{
// TODO a proper implementation
}
Concluding Remarks
After implementing the last four functions properly, the program is very well structured to be able to diagnose problems easily by changing what gets called from main.

Answer 3

Some crazy complicated answers have been posted.
Here it is in one loop, one printf, and one variable (other than the Width input).
#include <stdio.h>
#include <stdlib.h>
int main(void) {
int w = 9;
int l;
for(l=0; l < w; ++l)
{
printf("%*.*s\n",
abs(w/2 - l)+abs((2*l+1)-(2*l+1>w)*2*w),
abs((2*l+1)-(2*l+1>w)*2*w),
"# # # # # # # # # # # # # # # # # # ");
}
return 0;
}
Link to IDEOne Code