Can anyone figure out whats wrong with this.

[SepetMaster]

#include<stdio.h>
void main(void)
{
    int selection;

    printf("1) Energy Consumption Of Selected Year For A Selected Sector\n");
    printf("2) Yearly Average Energy Consumption\n");
    printf("3) Lowest Energy Consumption In Each Year\n");
    printf("4) Percentage Of Energy Consumption For Each Sector From 2010 to 2013\n");
    printf("5) Highest Energy Consumption And Its Corresponding Year For a Selected Sector\n");
    printf("6) Two Highest Energy Consumption Among All Sectors from 2010 to 2013\n");
    printf("Please enter 1,2,3,4,5 or 6\n");

    scanf_s("%d", &selection);

    switch (selection)
    {
    case 1:    
    {
        int selection;

        printf("1) EC in Industrial-Related\n");
        printf("2) EC in Commerce And Service-Related\n");
        printf("3) EC in Transport-Related\n");
        printf("4) EC in Household\n");
        printf("5) EC in Others\n");
        printf("Please enter 1,2,3,4 or 5\n");

        scanf_s("%d", &selection);

    }
    switch (selection)
    {
    case 1:
    {

        int selection;

        printf("1) 2010\n");
        printf("2) 2011\n");
        printf("3) 2012\n");
        printf("4) 2013\n");
        printf("Please enter 1,2,3 or 4\n");

        scanf_s("%d", &selection);
    }
    switch (selection)
    {
        case 1:
        printf("The Energy Consumption Is 11760.7\n");
        break;
        case 2:
        printf("The Energy Consumption Is 18059.1\n");
        break;
        case 3:
        printf("The Energy Consumption Is 18578.0\n");
        break;
        case 4:
        printf("The Energy Consumption Is 18830.1\n");
        break;

    }
    break;

    case 2:
    {

        int selection;

        printf("1) 2010\n");
        printf("2) 2011\n");
        printf("3) 2012\n");
        printf("4) 2013\n");
        printf("Please enter 1,2,3 or 4\n");

        scanf_s("%d", &selection);
    }
    switch (selection)
    {
    case 1:
        printf("The Energy Consumption Is 15165.4\n");
        break;
    case 2:
        printf("The Energy Consumption Is 15176.4\n");
        break;
    case 3:
        printf("The Energy Consumption Is 16136.4\n");
        break;
    case 4:
        printf("The Energy Consumption Is 16605.6\n");
        break;
    }
    break;

    case 3:
    {

        int selection;

        printf("1) 2010\n");
        printf("2) 2011\n");
        printf("3) 2012\n");
        printf("4) 2013\n");
        printf("Please enter 1,2,3 or 4\n");

        scanf_s("%d", &selection);
    }
    switch (selection)
    {
    case 1:
        printf("The Energy Consumption Is 2143.3\n");
        break;
    case 2:
        printf("The Energy Consumption Is 2278.6\n");
        break;
    case 3:
        printf("The Energy Consumption Is 2391.0\n");
        break;
    case 4:
        printf("The Energy Consumption Is 2370.0\n");
        break;
    }
    break;

    case 4:
    {

        int selection;

        printf("1) 2010\n");
        printf("2) 2011\n");
        printf("3) 2012\n");
        printf("4) 2013\n");
        printf("Please enter 1,2,3 or 4\n");

        scanf_s("%d", &selection);
    }
    switch (selection)
    {
    case 1:
        printf("The Energy Consumption Is 6647.5\n");
        break;
    case 2:
        printf("The Energy Consumption Is 6494.1\n");
        break;
    case 3:
        printf("The Energy Consumption Is 6641.0\n");
        break;
    case 4:
        printf("The Energy Consumption Is 6766.4\n");
        break;
    }
    break;

    case 5:
    {

        int selection;

        printf("1) 2010\n");
        printf("2) 2011\n");
        printf("3) 2012\n");
        printf("4) 2013\n");
        printf("Please enter 1,2,3 or 4\n");

        scanf_s("%d", &selection);
    }
    switch (selection)
    {
    case 1:
        printf("The Energy Consumption Is 534.9\n");
        break;
    case 2:
        printf("The Energy Consumption Is 459.0\n");
        break;
    case 3:
        printf("The Energy Consumption Is 454.3\n");
        break;
    case 4:
        printf("The Energy Consumption Is 350.8\n");
        break;
    }
    break;
}

[Salem]

Well I can see a few things wrong
- it uses void main where it should be int main
- it is badly indented
- you have multiple nested definitions of a variable called 'selection'.

In order to tell you what's wrong, you need to say
- what you type in
- what you get
- what you expected.