Getting the number of decimal places: Difference between revisions

=={{header|C}}==

<lang c>#include <stdio.h>

int findNumOfDec(double x) {

char buffer[128];

int pos, num;

sprintf(buffer, "%.14f", x);

pos = 0;

num = 0;

while (buffer[pos] != 0 && buffer[pos] != '.') {

pos++;

}

if (buffer[pos] != 0) {

pos++; // skip over the decimal

while (buffer[pos] != 0) {

pos++; // find the end of the string

}

pos--; //reverse past the null sentiel

while (buffer[pos] == '0') {

pos--; // reverse past any zeros

}

while (buffer[pos] != '.') {

num++;

pos--; // only count decimals from this point

}

}

return num;

}

void test(double x) {

int num = findNumOfDec(x);

printf("%f has %d decimals\n", x, num);

}

int main() {

test(12.0);

test(12.345);

test(12.345555555555);

test(12.3450);

test(12.34555555555555555555);

test(1.2345e+54);

return 0;

}</lang>

{{out}}

<pre>12.000000 has 0 decimals

12.345000 has 3 decimals

12.345556 has 12 decimals

12.345000 has 3 decimals

12.345556 has 14 decimals

1234500000000000060751116919315055127939946206157864960.000000 has 0 decimals</pre>