Why Can't I Write C Code Outside of Functions?

Code outside functions

In C , you cannot write code outside of functions. The only things you can have outside of functions are declarations such as global variable declarations (usually a bad idea), function declarations, and so on.

For example, the following code will not compile:

int l, k;
for (l = 1; l <= node; l++)
{
    for (k = 1; k <= node; k++)
    {
        flow[i][j] = capacity[i][j];
        flow[j][i] = 0;
    }
}

This code will give you the following error:

error: expected unqualified-id before ‘for’
error: expected constructor, destructor, or type conversion before ‘<=’ token
error: expected constructor, destructor, or type conversion before ‘++’ tok

To fix this error, you need to move the code into a function. For example, you could put it in a function called main like this:

int main()
{
    int l, k;
    for (l = 1; l <= node; l++)
    {
        for (k = 1; k <= node; k++)
        {
            flow[i][j] = capacity[i][j];
            flow[j][i] = 0;
        }
    }

    return 0;
}

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