Declarations:
int textheight(char *string);
int textwidth(char *string);
Function textheight returns the height of a string in pixels and textwidth function returns the width of a string in pixels.
C program
#include <graphics.h>
#include <stdio.h>
#include <conio.h>
#include <stdio.h>
#include <conio.h>
int main()
{
int gd = DETECT, gm, a, b;
char arr[100];
initgraph(&gd, &gm, "C:\\TC\\BGI");
a = textheight("H");
b = textwidth("H");
sprintf(arr,"Textheight = %d, Textwidth = %d",a,b);
outtext(arr);
getch();
closegraph();
return 0;
}