Best way to print the result of a bool as 'false' or 'true' in c?
I have to write a program in which main calls other functions that test a series of number if any are less than a number, if all the series' numbers are between two limits, and if any are negative. My code returns the values of 1 for true and 0 for false, but the assignment asks that they be printed as 'true' or 'false'. I'm not sure how to get the bool answers to print as a string from printf. I used if (atl == false) printf("false"); in my at_least.c and in main.c, but it returns only a long string of true or false (ex: truetruetrue....). I'm not sure if that is the correct coding and I'm putting it in the wrong spot or there was some other code that I need to use.
This is my main.c:
#include "my.h"
int main (void)
{
int x;
int count = 0;
int sum = 0;
double average = 0.0;
int largest = INT_MIN;
int smallest = INT_MAX;
bool atlst = false;
bool bet = true;
bool neg = false;
int end;
while ((end = scanf("%d",&x)) != EOF)
{
sumall(x, &sum); //calling function sumall
count++;
larger_smaller(x, &largest, &smallest); //calling function larger_smaller
if (atlst == false)
at_least(x, &atlst); //calling function at_least if x < 50
if (bet == true)
between(x, &bet); //calling function between if x is between 30 and 40 (inclusive)
if (neg == false)
negative(x, &neg); //calling function negative if x < 0
}
average = (double) sum / count;
print(count, sum, average, largest, smallest, atlst, bet, neg);
return;
}
my results for a set of numbers:
The number of integers is: 15
The sum is : 3844
The average is : 256.27
The largest is : 987
The smallest is : -28
At least one is < 50 : 1 //This needs to be true
All between 30 and 40 : 0 //This needs to be false
At least one is negative : 1 //This needs to be true
This is in C, which I can't seem to find much on.
Thanks in advance for your help!
ADDENDUM:
This is repeated from an answer below.
This worked for the at_least and negative开发者_Python百科 functions, but not for the between function. I have
void between(int x, bool* bet)
{
if (x >= LOWER && x <= UPPER)
*bet = false;
return;
}
as my code. I'm not sure what's wrong.
Alternate branchless version:
"false\0true"+6*x
You could use C's conditional (or ternary) operator :
(a > b) ? "True" : "False";
or perhaps in your case:
x ? "True" : "False" ;
x ? "true" : "false"
The above expression returns a char *
, thus you can use like this:
puts(x ? "true" : "false");
or
printf(" ... %s ... ", x ? "true" : "false");
You may want to make a macro for this.
So what about this one:
#include <stdio.h>
#define BOOL_FMT(bool_expr) "%s=%s\n", #bool_expr, (bool_expr) ? "true" : "false"
int main(int iArgC, char ** ppszArgV)
{
int x = 0;
printf(BOOL_FMT(x));
int y = 1;
printf(BOOL_FMT(y));
return 0;
}
This prints out the following:
x=false
y=true
Using this with type bool but int should work the same way.
I have three arrays for that:
strbool.c
:
#include "strbool.h"
const char alx_strbool[2][6] = {"false", "true"};
const char alx_strBool[2][6] = {"False", "True"};
const char alx_strBOOL[2][6] = {"FALSE", "TRUE"};
strbool.h
:
#pragma once
/* rename without alx_ prefix */
#if defined(ALX_NO_PREFIX)
#define strbool alx_strbool
#define strBool alx_strBool
#define strBOOL alx_strBOOL
#endif
extern const char alx_strbool[2][6];
extern const char alx_strBool[2][6];
extern const char alx_strBOOL[2][6];
Disclaimer: The prefixes are necessary because names starting with str
are reserved (actually, only strbool
), but until they are actually used by C or POSIX, I will use the short version.
It's very simple to use them:
#include <stdio.h>
#define ALX_NO_PREFIX
#include "strbool.h"
int main(void)
{
int var = 7;
printf("var is %s\n", strBool[!!var]);
return 0;
}
var is True
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