C語言實現一維卷積程式碼（失敗）待修改

#include<iostream>
using namespace std;
int main()
{
	int i,j,k,n,m,a[n],b[m],c[n+m-1];
	cout<<"輸入n:";
	cin>>n;
	cout<<endl;
	cout<<"輸入m:";
	cin>>m;
	cout<<endl;
	cout<<"輸入a序列"<<endl;
	for(i=0;i<n;i++)
		cin>>a[i];
	cout<<"輸入b序列"<<endl;	
	for(j=0;j<m;j++)
		cin>>b[j];
		c[0]=0;
	for(j=0;j<n+m-1;j++)
	{
		for(k=0;k<=j;k++)
		{
			if((m>(m+k-j-1)>=0)&&(k<n))
			{
			c[j]+=a[k]*b[m+k-j-1];
			}
		}
	}
	for(i=0;i<n+m-1;i++)
	cout<<c[i]<<endl;
 }