Need help on 2 programs

I am trying to code two programs for uni. I am almost there, I can feel it! But not quite.

For starters; this code here, I'm trying to run but I'm not too sure on how to fix the errors The errors state Expected '(' before 'radius' (line 101:9) Expected 'while' before 'case' case 2: (line 129:2 Expected 'while' before 'default' (line 185:5)

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <math.h>
#include <string.h>
#define PI 3.14159 


//DIAMETER TO RADIUS 
double diameter_to_radius(double radius)
{
return radius * 2;
}

//RANDOM VALUE GENERATOR
double random_value_generator(int Rand_MIN, int Rand_MAX)
{

double Rand_Value;
double range = (Rand_MAX - Rand_MIN);
double div = range / Rand_MAX;
Rand_Value = Rand_MIN + (rand() * div);

return Rand_Value;
}

//AREA CALCULATION
double area(double radius, double diameter)
{
if (radius < diameter)
{
    return PI*(radius* radius);
}
else
{
return PI*diameter;
}
}

//CIRCUMFEREnCE CALCULATION 
double circumference(double radius, double diameter)
{
if (radius < diameter)
{
    return  2 * PI * radius;
}
else
{
return PI*diameter;
}
}

int main()
{
double diameter;
double radius;
int NumCode;
int NumCode2;
int NumCode3;
char Unit;
char Calculate;
double Rand_Value;


// Is a Menu for usability 
do {    
printf( "1. Enter 1 for RADIUS    \n" );
printf( "2. Enter 2 for DIAMETER       \n" ); 
printf( "-1. Exit                \n" );
printf( "Code Selected: " );
scanf( "%d", &NumCode );

switch (NumCode)
    {
case 1:

    do {
    printf( "1. Enter 1 for CM    \n" );
    printf( "2. Enter 2 for M     \n" ); 
    printf( "-1. Exit                \n" );
    printf( "Code Selected: " );
    scanf( "%d", &NumCode3 );   

    switch(NumCode3)
    {
    case 1:     
    printf("You have selected CM \n");
    scanf("%s", Unit);
    break;

    case 2:
    printf("You have selected M\n");
    break;

    default:            
    printf( "You have entered an invalid choice\n" );
    break;
    }
    }

    while radius = random_value_generator(0,15); // for the radius

    printf("The radius given by random generator is: %2.2f %s\n",Rand_Value,Unit);

    do {
    printf( "1. Enter 1 for AREA    \n" );
    printf( "2. Enter 2 for CIRCUMFERENCE       \n" ); 
    printf( "-1. Exit                \n" );
    printf( "Code Selected: " );
    scanf( "%d", &NumCode2 );   

    switch(NumCode2)
    {
    case 1: 
        diameter = 0;
        printf("Area of circle with radius of %f is %5.2f %s\n", radius,area(radius,diameter),Unit);
        break;

    case 2:
        printf("Circumference of circle with radius of %2.2f is %2.2f %s\n",radius,circumference(radius,diameter),Unit);
        break;

   default:            
    printf( "You have entered an invalid choice\n" );
    break;
    }
    } //Code stops 

case 2: 

    do {
        printf( "1. Enter 1 for CM    \n" );
        printf( "2. Enter 2 for M     \n" ); 
        printf( "-1. Exit                \n" );
        printf( "Code Selected: " );
        scanf( "%d", &NumCode3 );   

    switch(Measurement)
    {
    case 1:     
    printf("You have selected CM \n");
    scanf("%s", Unit);
    break;

    case 2:
    printf("You have selected M\n");
    break;

    default:            
    printf( "You have entered an invalid choice\n" );
    break;
    }
    }

    radius = random_value_generator(0,15); // for the diameter


    printf("The diameter given by random generator is: %2.2f %s\n",diameter_to_radius(radius),Unit);
    printf("The corresponding radius is: %2.2f %s\n",radius,Unit);

    do {
    printf( "1. Enter 1 for AREA    \n" );
    printf( "2. Enter 2 for CIRCUMFERENCE       \n" ); 
    printf( "-1. Exit                \n" );
    printf( "Code Selected: " );
    scanf( "%d", &NumCode2 );   

    switch(Calculate)
    {
    case 1: 
        diameter = 0;
        printf("Area of circle with diameter of %f is %5.2f     %s\n",diameter_to_radius(radius),area(radius,diameter),Unit);
        break;

    case 2:
        printf("Circumference of circle with diameter of %2.2f is %2.2f     %s\n", diameter_to_radius(radius),circumference(radius,diameter),Unit);
        break;

   default:            
    printf( "You have entered an invalid choice\n" );
    break;
    }
    }

   default:            
    printf( "You have entered an invalid choice\n" );
    break;
    }

}while(NumCode!=-1);
return 0;
}

Secondly; My second program works... Not really. The values it outputs are redicously high and not what its meant to do. Im not sure what I should do to fix it nor the problem. Im meant to: Write a complete C program to do the following tasks: (i) Read a positive integer from user as the value of m (need to verify that m is positive but less than 30). (ii) Read in the m elements (up to 30) of a one-dimensional floating point array, compute the sum of these elements, the mean, the deviation, and the standard deviation.

This is the code I've done so far.

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <math.h>
int main()
{
int i;
i = 0;
float mean;
float deviation;
float standard_deviation;
int integer;
int z;


printf("Input a positive integer: ");
scanf("%d",&integer);

int x[integer];

while(i<1)
{
    if((integer > 0) && (integer < 30))
    {

        for(z=0; z<integer;z++)
        {

            srand(time(NULL));
            printf("x[%d]=%d\n",z,x);
            mean = mean + x[z];

        }

        mean = mean/integer;
        printf("Mean is %.2f\n",mean);
        for(z = 0; z < integer; z++)
        {
            deviation = x[z] - mean;
            printf("Deviation is [x = %.2f] = %.2f\n",z,deviation);
        }

        printf("Standard Deviation = %.2f\n", standard_deviation);

        i++;
    }
    else
    {

        printf("Wrong input, please try again \n");
        printf("Input a positive integer: ");
        scanf("%d\n",&integer);
    }
}
return 0;
}

Would be good if you guys couyld help me! TRhanks