If you just want to round the number for output purposes, then the "%.2f" format string is indeed the correct answer. However, if you actually want to round the floating point value for further computation, something like the following works:
#include <math.h>
float val = 37.777779;
float rounded_down = floorf(val * 100) / 100; /* Result: 37.77 */
float nearest = roundf(val * 100) / 100; /* Result: 37.78 */
float rounded_up = ceilf(val * 100) / 100; /* Result: 37.78 */
Notice that there are three different rounding rules you might want to choose: round down (ie, truncate after two decimal places), rounded to nearest, and round up. Usually, you want round to nearest.
As several others have pointed out, due to the quirks of floating point representation, these rounded values may not be exactly the "obvious" decimal values, but they will be very very close.
For much (much!) more information on rounding, and especially on tie-breaking rules for rounding to nearest, see the Wikipedia article on Rounding.
Answer from Dale Hagglund on Stack OverflowReddit
reddit.com › r/c_programming › maximum decimal places
r/C_Programming on Reddit: Maximum decimal places
June 10, 2020 -
What is the maximum decimal places that can be stored using c? I tried to store - 1.86264514923107200935514487085e-09 but only got 0.00000000186264514923107200000000.....
Top answer 1 of 5
3
https://en.wikipedia.org/wiki/Double-precision_floating-point_format Significant precision is 53 bits = 9.00719925e15, so that's 15 (almost 16) decimal digits of significance
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If you care about preserving the value across a complete decimal → floating-point → decimal round-trip: #include #include int main(void) { printf("FLT_DIG = %d\n", FLT_DIG); printf("DBL_DIG = %d\n", DBL_DIG); printf("LDBL_DIG = %d\n", LDBL_DIG); } On my system, I get: FLT_DIG = 6 DBL_DIG = 15 LDBL_DIG = 18 Note that this does not mean that all values with at most this many decimal digits can be represented "exactly". It just means that the round-trip will yield the same decimal digits at the end. Note also that "decimal digits" here is not just the digits after the decimal point. 1234.56 has 6 significant decimal digits. If stored in a float and then reformatted as a decimal value, it will yield the same decimal value on my system. But 1234.567 has 7 significant decimal digits, and this is not guaranteed to yield the same decimal value if round-tripped through a float on my system. If you care about a floating-point → decimal → floating-point round-trip, you need more decimal digits: #include #include int main(void) { printf("FLT_DECIMAL_DIG = %d\n", FLT_DECIMAL_DIG); printf("DBL_DECIMAL_DIG = %d\n", DBL_DECIMAL_DIG); printf("LDBL_DECIMAL_DIG = %d\n", LDBL_DECIMAL_DIG); } I get: FLT_DECIMAL_DIG = 9 DBL_DECIMAL_DIG = 17 LDBL_DECIMAL_DIG = 21 These values are greater than the ones before because round-tripping in this direction needs to preserve the precision in the original floating-point value.
Top answer 1 of 16
489
If you just want to round the number for output purposes, then the "%.2f" format string is indeed the correct answer. However, if you actually want to round the floating point value for further computation, something like the following works:
#include <math.h>
float val = 37.777779;
float rounded_down = floorf(val * 100) / 100; /* Result: 37.77 */
float nearest = roundf(val * 100) / 100; /* Result: 37.78 */
float rounded_up = ceilf(val * 100) / 100; /* Result: 37.78 */
Notice that there are three different rounding rules you might want to choose: round down (ie, truncate after two decimal places), rounded to nearest, and round up. Usually, you want round to nearest.
As several others have pointed out, due to the quirks of floating point representation, these rounded values may not be exactly the "obvious" decimal values, but they will be very very close.
For much (much!) more information on rounding, and especially on tie-breaking rules for rounding to nearest, see the Wikipedia article on Rounding.
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130
Using %.2f in printf. It only print 2 decimal points.
Example:
printf("%.2f", 37.777779);
Output:
37.77
how do u remove value after decimal in c like 69.000000 i want to remove the 0 after decimal
Post a snipper of your current code and we'll tell you how to best modify it to suit your behaviour. It depends on how you want other, non-round values to behave, i.e. if you want 69.2 to be 69 or 69.2 Vaguely, your options are: Cast it to int, and print as an int Round up / down Use the correct format specifier if you're using printf (so %2.0f or %g) More on reddit.com
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4
April 14, 2023How to limit user to input a float with one decimal point in C - Stack Overflow
Program to limit the user's input to one decimal point in C. For example: Enter grade: 5 //Acceptable Enter grade: 8.5 //Acceptable Enter grade: 6.467 //Not acceptable, Re-enter grade #include... More on stackoverflow.com
floating point - How do I write only the decimal places in C language? - Stack Overflow
If I have 2.55, how do I write only .55 and skip 2 in programming language? More on stackoverflow.com
Maximum decimal places
https://en.wikipedia.org/wiki/Double-precision_floating-point_format Significant precision is 53 bits = 9.00719925e15, so that's 15 (almost 16) decimal digits of significance More on reddit.com
6
1
June 10, 2020Videos
02:01
C 16: Round and display a number to 2 decimal places using the ...
08:10
Round A Double To A Specific Number Of Decimal Places | C Programming ...
07:30
C Programming Example: Removing Decimal Part from an Integer - YouTube
05:05
Round off decimal number to 2 places in c++ using 2 ways - YouTube
W3Schools
w3schools.com › c › c_data_types_dec.php
C Data Types Decimal Precision
You have probably already noticed ... Yourself » · If you want to remove the extra zeros (set decimal precision), you can use a dot (.) followed by a number that specifies how many digits that should be shown after the decimal ...
YouTube
youtube.com › coffee programmer
C Programming Limiting floats to two decimal places - How to limit and display float variable values - YouTube
Can you help me to buy a coffee:https://www.buymeacoffee.com/coffeeprogram how to limit float to 2 decimal places in c
Published October 12, 2022 Views 2K
GeeksforGeeks
geeksforgeeks.org › c language › g-fact-41-setting-decimal-precision-in-c
Setting decimal precision in C - GeeksforGeeks
January 10, 2025 - How to print floating point numbers with a specified precision? Rounding is not required. For example, 5.48958123 should be printed as 5.4895 if given precision is 4. For example, below program sets the precision for 4 digits after the decimal point: ... // C program to set precision in floating point numbers #include<stdio.h> #include<math.h> int main() { float num = 5.48958123; // 4 digits after the decimal point num = floor(10000*num)/10000; printf("%f", num); return 0; }
Northern Michigan University
nmu.edu › Webb › ArchivedHTML › MathComputerScience › c_programming › c_008.htm
More About Float and Double Variables
To change the number of decimal places printed out for float or double variables, modify the %f or %e to include a precision value, eg, ... In this case, the use of %.2f limits the output to two decimal places, and the output now looks like
Quora
quora.com › How-do-you-handle-the-rounding-of-decimal-places-in-C-C-float-rounding-development
How to handle the rounding of decimal places in C (C, float, rounding, development) - Quora
The C standard math library has ... 3 decimal places - then multiply the number by 1000, use the ceil, floor or round function depending on which way you want to round - then divide by 1000....
YouTube
youtube.com › watch
Setting Decimal Precision in C - YouTube
Setting Decimal Precision in CGreetings, in this C tutorial we shall be looking at how to specify how many decimal places we print out for a float or double ...
Published July 15, 2023
GeeksforGeeks
geeksforgeeks.org › c language › rounding-floating-point-number-two-decimal-places-c-c
Rounding Floating Point Number To two Decimal Places in C and C++ - GeeksforGeeks
May 21, 2024 - #include <iostream> using namespace std; float round(float var) { // we use array of chars to store number // as a string. char str[40]; // Print in string the value of var // with two decimal point sprintf(str, "%.2f", var); // scan string value in var sscanf(str, "%f", &var); return var; } int main() { float var = 37.66666; cout << round(var); return 0; }
Quora
quora.com › How-do-I-round-off-a-float-to-2-decimal-points-in-C-like-3-01943-to-3-02
How to round off a float to 2 decimal points in C, like 3.01943 to 3.02 - Quora
Answer (1 of 7): If you have to round input floating point number then for that the format is “%wf” where w = Integer number for total width of data.(including the digit before and after decimal and decimal itself) Ex- scanf(“”,&x) For x = 3.01943 Result = 7.8 If you have to round output fl...
Linux Hint
linuxhint.com › setting_decimal_precision_c_-language
Setting Decimal Precision in C – Linux Hint
One method of adjusting the decimal precision of a variable is to multiply it by a factor of 10, 100, or some other multiple of 10 depending on what precision you want to achieve, and round the result with the ceilf() function.
Quora
quora.com › How-do-you-get-6-decimal-places-in-C-How-do-you-limit-decimal-places-in-C
How to get 6 decimal places in C++? How do you limit decimal places in C++ - Quora
Answer (1 of 8): If you are just printing the number by rounding it off to 6 decimal place then use [code]printf("%.6f",N); [/code]or you can also use [code]cout using namespace std; int main() { double N ...
Reddit
reddit.com › r/cprogramming › how do u remove value after decimal in c like 69.000000 i want to remove the 0 after decimal
r/cprogramming on Reddit: how do u remove value after decimal in c like 69.000000 i want to remove the 0 after decimal
April 14, 2023 - Convert it to string, use regex to extract text before decimal point and then just print it.
Homedutech
homedutech.com › program-example › how-to-restrict-a-float-value-to-only-two-places-after-the-decimal-point-in-c.html
How to restrict a float value to only two places after the decimal point in C?
In C, you can restrict a float value to only two decimal places for display purposes by using the printf function with a format specifier that specifies the precision.
w3tutorials
w3tutorials.net › blog › how-do-i-restrict-a-float-value-to-only-two-places-after-the-decimal-point-in-c
How to Restrict a Float to Two Decimal Places in C: Rounding Techniques Explained — w3tutorials.net
Not suitable for calculations: ... float to two decimal places (e.g., for storage or further calculations), use the "multiply-round-divide" technique....
Top answer 1 of 4
1
You will have to input the data as string, then check it only has one decimal place.
It is not possible to input a floating-point value and then check for decimal places; since the floating point values are stored internally with binary places and hold an approximation of the value that was input, in most cases.
The input code could look like:
char temp[20];
if ( 1 != scanf("%19s", temp) )
return EXIT_FAILURE;
// code to check for decimal place goes here - I'm purposefully not
// showing it as this looks like homework!
// once we have checked that the input is correct, then convert to double
grade[i] = strtod(temp, NULL);
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#include <stdio.h> // printf(), scanf()
#include <math.h> // floor()
main()
{
double grade[8];
int i;
for (i = 0; i < 8; i++)
{
do
{
printf("Insert grade: ");
scanf("%lf", &grade[i]);
grade[i] *= 10;
if (grade[i] != floor(grade[i])) // Prints error message, if user types more than one decimal point
{
printf("Grade must have one decimal point.\nPlease re-enter grade.\n");
}
}while (grade[i] != floor(grade[i])); // Checks decimal point
}
}
Oxford University
mathcenter.oxford.emory.edu › site › cs170 › printf
The printf Method
How do we print just an approximation of a variable's value (to some number of decimal places)? Interestingly, it is possible to creatively use casting and promotion to print a "double" value with only two decimal places.
HPE
support.hpe.com › hpesc › public › docDisplay
C: How to round off to the nearest two decimal places
We cannot provide a description for this page right now
Academic Help
academichelp.net › coding › c-coding › how-to-print-a-double.html
How to Print a Double in C With Precision
January 31, 2024 - Double-precision floating-point numbers have limited precision, which can lead to rounding errors. To mitigate rounding errors, limit the number of decimal places you print using the %.<n>f format specifier, as shown earlier.
Top answer 1 of 4
3
Well you can do this to store it in another variable -
double a=2.55,b;
b =a-(long)a; // subtracting decimal part from a
printf("%.2f\n",b);
As pointed out by Mark Dickinson Sir in comment that this is not safe . So you can make use of function modf from <math.h>-
For example -
double a=-2.55,b,i;
b =modf(a,&i); // i will give integer part and b will give fraction part
printf("%.2f\n",b);
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2
One dirty trick is to cast your double to an int to get only the whole number. You can then subtract the two to get only the decimal part:
double d = 2.55;
double remainder = d - (int)d;
printf ("%.2f\n", remainder);