Thread: trying to implement graph(data structure)

Code:

#include<stdio.h>

struct node
{

	struct node *edge[10];
	int wt[10],id;
} ver[10];

int makegraph()
{
	int i=0,j=0,nov=0;
	char ch;
	printf("Enter number of vertices in the graph");
	scanf("%d",&nov);
	for(i=0;i<nov;i++)
	{
		ver[i].id=i;
		for(j=0;j<nov;j++)
		{
			printf("Is there any edge between vertex %d and %d(y/n)\n",i,j);
			scanf("%c",&ch);
			if(ch=='y')
			{
				ver[i].edge[j]=&ver[j];
				printf("Enter the weight of the edge between %d and %d");
				scanf("%d",&ver[i].wt[j]);
			}
		}
	}
	return nov;
}

void showgraph(int nov)
{
	int i,j;
	for(i=0;i<nov;i++)
	{
		printf("ver[%d]:-\nEdges:-",i);			
		for(j=0;j<nov;j++)
		{
			printf("(%d,%d),",ver[i].edge[j]->id,ver[i].wt[j]);
		}
	}
}

int main()
{
	showgraph(makegraph());
	return 0;
}

it compiles in gcc 4.3 but when i run the program it skips some of the scanf statements, for example

after it asks enter the number of vertices
it asks
"Is there any edge between vertex 0 and 0(y/n)"
but does not let me give any input it simply skips to the next question
"Is there any edge between vertex 0 and 1(y/n)"
and waits for my input

why is this happening? how to fix this?

enter-key is a character, just like y and n. If you want your scanf statements to not "see" whitespace, you have to have the format skip whitespace, as in " %c" (instead of just "%c").

thanks