Why can I call the undefined function sqrt() in C? [duplicate] - c

This question already has answers here:
Why does C allow me to call an undeclared function? [duplicate]
(1 answer)
Function assigns incorrect float value in C
(1 answer)
Closed 3 years ago.
Hey guys I was wondering why my program was just returning junk and I found out that I didn't include math.h. But why did the code even compile and run if there isn't any definition for the function ?
#include <stdio.h>
int main()
{
int ka = 0;
ka = sqrt(4);
printf("ha ist %d", ka);
system("PAUSE");
return 0;
}

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Power of 5 and its multiples do not work properly in VS code [duplicate]

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Why the result of pow(10,2) 99 instead of 100? [duplicate]
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Strange behaviour of the pow function
(5 answers)
Closed 28 days ago.
when i use pow() function in Vscode editior it works properly for all digits execpt 5 and its mulitples
#include<stdio.h>
#include<math.h>
int main(){
int a = 25;
int b = pow(a,2);
printf("%d",b);
return 0;
}

Return string after changing it in C [duplicate]

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Function returning address of local variable error in C
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returning a local variable from function in C [duplicate]
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How to access a local variable from a different function using pointers?
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Closed 4 months ago.
I know, there are multiple questions about this on StackOverflow but I couldn't find a fitting solution for my problem.
I want to generate product codes (e.g. 12a, important: numbers and letters) and return them and printf. But when I do it in my main I get no result. When I printf("%s\n", pcode) in my generator function it works, but after return pcode I won't get the result.
char* generate(int num) {
char pcode[3];
... // generating code
printf("%s\n", pcode); // correct output
return pcode;
}
int main(void) {
printf("%s\n", generate(12)); // wrong output
}

why does my clrscr function isn't working [duplicate]

This question already has answers here:
Function clrscr in C and C++
(5 answers)
"UNDEFINED REFRENCE TO clrscr();" [duplicate]
(2 answers)
Closed 2 years ago.
I'm a new C programming learner. I'm writing a code by including stdio.h and conio.h but if I write clrscr(); inside my code, it isn't working. If I remove the part clrscr(); it's working. Why??
Here's the source code:
#include<stdio.h>
#include<conio.h>
void main()
{
clrscr();
printf("A tab \tis used in this line.");
getch();
}

"warning: division by zero [-Wdiv-by-zero]" when not dividing by zero [duplicate]

This question already has answers here:
C program to convert Fahrenheit to Celsius always prints zero
(6 answers)
Closed 3 years ago.
My code for the following simple coding exercise produces a "division by zero" warning, and I'm wondering why.
#include <stdio.h>
int main() {
for(int i = 0; i < 100; i++) {
printf("celsius=%d fahrenheit=%d\n", i, (i/(5/9))+32);
}
return 1;
}
temps.c: In function ‘main’:
temps.c:6:45: warning: division by zero [-Wdiv-by-zero]
printf("celsius=%d fahrenheit=%d\n", i, (i/(5/9))+32);
I realised while writing this question that it's because I should have written 5.0/9.0, since C handles division with integers in a way that I didn't expect. Posting this anyway since I couldn't find this particular error linked to this particular problem on SO.

Power fucntion langage C code blockss compiler [duplicate]

This question already has answers here:
To the power of in C? [duplicate]
(7 answers)
Closed 7 years ago.
void sommeascf(n)
for(i=1; i<=n; i++){
result= result+ 1/i^n
}
}
the problem I'm facing is :
result = result + 1/i^n
How can I put the power function into this arithmetic operation ?
^ this is bitwise XOR operator in C . You can write that expression using pow function like this -
result= result+ 1/(pow(i,n));
Note - You need to include header <math.h>

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