can u write a program in C which gives the no of digits before n after a decimal point in a floating point num

Answer 1

the easy way is, get floor value of the given number, which is number before decimal.

then substract as given number - floor number is number after decimal.

Answer 2

Finding the number of digits before the decimal point is easy - log10() function will do the job.
The number of digits _after_ the decimal point is tricky. The fact, that a number is 1.5 rather than 1.499999999999 is a happenstance, defined by the particular platform and compiler.

You may take your chances with the following:

float your_floating_number;
int result;
char string[25];
sprintf(string, "%f", your_floating_number);
result = strlen(strchr(string,'.')) - 1;