Task: Display a linear combination
C: #include<stdlib.h>
#include<stdio.h>
#include<math.h> 

int main(int argC, char* argV[])
{
	
	int i,zeroCount= 0,firstNonZero = -1;
	double* vector;
	
	if(argC == 1){
		printf("Usage : %s <Vector component coefficients seperated by single space>",argV[0]);
	}
	
	else{
		
		printf("Vector for [");
		for(i=1;i<argC;i++){
			printf("%s,",argV[i]);
		}
		printf("\b] -> ");
		
		
		vector = (double*)malloc((argC-1)*sizeof(double));
		
		for(i=1;i<=argC;i++){
			vector[i-1] = atof(argV[i]);
			if(vector[i-1]==0.0)
				zeroCount++;
			if(vector[i-1]!=0.0 && firstNonZero==-1)
				firstNonZero = i-1;
		}

		if(zeroCount == argC){
			printf("0");
		}
		
		else{
			for(i=0;i<argC;i++){
				if(i==firstNonZero && vector[i]==1)
					printf("e%d ",i+1);
				else if(i==firstNonZero && vector[i]==-1)
					printf("- e%d ",i+1);
				else if(i==firstNonZero && vector[i]<0 && fabs(vector[i])-abs(vector[i])>0.0)
					printf("- %lf e%d ",fabs(vector[i]),i+1);
				else if(i==firstNonZero && vector[i]<0 && fabs(vector[i])-abs(vector[i])==0.0)
					printf("- %ld e%d ",labs(vector[i]),i+1);
				else if(i==firstNonZero && vector[i]>0 && fabs(vector[i])-abs(vector[i])>0.0)
					printf("%lf e%d ",vector[i],i+1);
				else if(i==firstNonZero && vector[i]>0 && fabs(vector[i])-abs(vector[i])==0.0)
					printf("%ld e%d ",vector[i],i+1);
				else if(fabs(vector[i])==1.0 && i!=0)
					printf("%c e%d ",(vector[i]==-1)?'-':'+',i+1);
				else if(i!=0 && vector[i]!=0 && fabs(vector[i])-abs(vector[i])>0.0)
					printf("%c %lf e%d ",(vector[i]<0)?'-':'+',fabs(vector[i]),i+1);
				else if(i!=0 && vector[i]!=0 && fabs(vector[i])-abs(vector[i])==0.0)
					printf("%c %ld e%d ",(vector[i]<0)?'-':'+',labs(vector[i]),i+1);				
			}
		}
	}
	
	free(vector);
	
	return 0;
}

VB: Imports System.Text

Module Module1

    Function LinearCombo(c As List(Of Integer)) As String
        Dim sb As New StringBuilder
        For i = 0 To c.Count - 1
            Dim n = c(i)
            If n < 0 Then
                If sb.Length = 0 Then
                    sb.Append("-")
                Else
                    sb.Append(" - ")
                End If
            ElseIf n > 0 Then
                If sb.Length <> 0 Then
                    sb.Append(" + ")
                End If
            Else
                Continue For
            End If

            Dim av = Math.Abs(n)
            If av <> 1 Then
                sb.AppendFormat("{0}*", av)
            End If
            sb.AppendFormat("e({0})", i + 1)
        Next
        If sb.Length = 0 Then
            sb.Append("0")
        End If
        Return sb.ToString()
    End Function

    Sub Main()
        Dim combos = New List(Of List(Of Integer)) From {
            New List(Of Integer) From {1, 2, 3},
            New List(Of Integer) From {0, 1, 2, 3},
            New List(Of Integer) From {1, 0, 3, 4},
            New List(Of Integer) From {1, 2, 0},
            New List(Of Integer) From {0, 0, 0},
            New List(Of Integer) From {0},
            New List(Of Integer) From {1, 1, 1},
            New List(Of Integer) From {-1, -1, -1},
            New List(Of Integer) From {-1, -2, 0, -3},
            New List(Of Integer) From {-1}
        }

        For Each c In combos
            Dim arr = "[" + String.Join(", ", c) + "]"
            Console.WriteLine("{0,15} -> {1}", arr, LinearCombo(c))
        Next
    End Sub

End Module