Why am I receiving error codes with my program? Can someone fix the problem without changing the MAIN function. Thanks!!!( This is C programming )

#include

#include

int Add(int a, int b)

{

return a + b;

}

int Mult(int a, int b)

{

return a*b;

}

int IAvg(int a, int b)

{

return (a + b) / 2;

}

float FAvg(int a, int b)

{

return (a + b) / 2;

}

int Big(int a, int b)

{

if (a >= b)

{

return a;

}

return b;

}

int Small(int a, int b)

{

if (a <= b)

{

return a;

}

return b;

}

int Max(int* a, int size)

{

int i = 0;

int max = 0;

for (i = 0; i < size; i++)

{

if (max < a[i])

{

max = a[i];

}

}

return max;

}

int Min(int* a, int size)

{

int i = 1;

int min = a[0];

for (i = 1; i < size; i++)

{

if (min > a[i])

{

min = a[i];

}

}

return min;

}

int Sum(int* a, int size)

{

int i = 0;

int sum = 0;

for (i = 0; i < size; i++)

{

sum = sum + a[i];

}

return sum;

}

char numVowels(char phrase[])

{

for(i=0;i

{

if(phrase[i]=='a' || phrase[i]=='A' || phrase[i]=='e' || phrase[i]=='E' || phrase[i]=='i' || phrase[i]=='I' || phrase[i]=='o' || phrase[i]=='O' || phrase[i]=='u' || phrase[i]=='U')

vow=vow+1;

}

return vow;

}

void niceline(int i, char s, char m)

{

int j = i - 2;

int k = 0;

printf("%s", s);

for (k = 0; k < j; k++)

{

printf("%s", m);

}

printf("%s", s);

}

void box(int i, int j, char s, char m)

{

int k = 0;

for (k = 0; k < j; k++)

{

printf("%s", s);

}

for (k = 0; k < i - 2; k++)

{

niceline(7, s, m);

}

for (k = 0; k < j; k++)

{

printf("%s", s);

}

}

int main()

{

int a, b, c;

float f;

a = 5;

b = 4;

printf("Using values %d and %d ", a, b);

c = Add(a, b);

printf("Add %d ", c);

c = Mult(a, b);

printf("Mult %d ", c);

c = IAvg(a, b);

printf("IAvg %d ", c);

f = FAvg(a, b);

printf("FAvg %.2f ", f);

c = Big(a, b);

printf("Big %d ", c);

c = Small(a, b);

printf("Small %d ", c);

int nums[12] = { 22,43,35,8,43,17,54,41,29,48,36,19 };

int many = 12;

for (a = 0; a < many; ++a)

{

printf("%2d ", nums[a]);

printf(" ");

}

printf("max: %2d ", Max(nums, many));

printf("min: %2d ", Min(nums, many));

printf("sum: %2d ", Sum(nums, many));

char phrase[] = "DSU ... in Madison SD since 1881";

printf("String:: %s ", phrase);

many = numVowels(phrase);

printf("There are %d vowels ", many);

niceline(6, 'a', 'b');

niceline(7, '2', '1');

box(4, 5, '@', ' ');

box(6, 3, ' ', '#');

return 0;

}