what about c++ its giving me issues

You have  a bunch of compiler errors. Below code now compiles. See "you forgot" to see minor changes.

#include <stdio.h>   // you forgot to include this include

int  minimum (int  scores[4] [3])
{

    int  min, i,j;
min = scores[0][0];

for ( i = 0;  i<4;  ++i )
for (j=0; j<3; ++j)
if ( scores[i][j] < min )
min= scores[i][j];
return min;

}

//function for Maximum Value
int maximum (int values[4][3])
{
int  max, i,j;

max = values[0][0];

for ( i = 0;  i<4;  ++i )
  for (j=0; j<3; ++j)
if ( values[i][j] > max )
max= values[i][j];
return max;

}

//function for Average
float average (int values[4][3])
{float  sum=0.0;
int count=0;
float Average;
int i,j;

for(i=0;i<4;++i)
  for(j=0;j<3;++j)
{
sum=sum+values[i][j];
++count;
}
Average=sum/count;
return Average;
}



//function to find student average
float studentavg (int values[4][3])
{       // you forgot the {
float finalmark;

finalmark=values[0][0];
{

for ( int j=0;j<3;++j){  // you forgot to declare j as an int; replaced i with j

  for( int i=0;i<4;++i){  // you forgot to declare i as an int
  
 int rowsum=rowsum+values[i][j];

finalmark=rowsum/3;
printf("Student's final mark is %.2f\n", finalmark);
}

}
} ////  I think you forgot a couple of }
} ////  Hard to tell due to lack of consistent indentation

//Main Program
int main (void)
{
	int  values[4][3], i,j,min,max,sum=0,count=0;
	float Average,finalmark;
	int rowsum=0;
int  minimum (int  values[4][3]);
int maximum (int values[4][3]);
float average (int values[4][3]);
float studentavg (int values[4][3]);


printf ("Enter Values: \n");
	for ( i = 0; i< 4; i++ ) {

      for ( j = 0; j< 3; j++ ) {
         printf(" values[%i][%i] = ", i,j, values[i][j] );
         scanf("%i", &values[i][j]);
      }
   }
   printf("\n");
   printf("\n");
   printf("\n");      


min = minimum(values);
max = maximum(values);
Average = average(values);
finalmark=studentavg(values);


printf(" The minimum value is %i\n", min);
printf(" The maximum value is %i\n", max);
printf (" The Class final mark is %.2f\n", Average);


return 0;
}
           // you forgot to get rid of these extra }
//    }  // probably due to lack of proper indentation
    
// }

Select all Open in new window

 (Also, when posting, use the code tags - hit the CODE button in the post to create the tags, and insert the code between the tags.)