c89

This question already has answers here : Does Function pointer make the program slow? (8 answers) Closed 2 years ago . We know that using function pointers in C can be quite helpful when used in the proper scenarios (calling a function at runtime vs compile time, making the code more readable, etc.), but there isn't much literature around simple function invocation vs using a function pointer. void foo(void) { printf("hello\n"); } int testFcn(void) { // simple invokation foo(); return 0; } // Or, declare function pointer and assign void (*myFunc)(void) = foo; int testFcn(myFunc) { // Function

Are signed/unsigned mismatches necessarily bad? Here is my program: int main(int argc, char *argv[]) { unsigned int i; for (i = 1; i < argc; i++) { // signed/unsigned mismatch here } } argc is signed, i is not. Is this a problem? "signed/unsigned mismatches" can be bad. In your question, you are asking about comparisons. When comparing two values of the same base type, but one signed and one unsigned, the signed value is converted to unsigned. So, int i = -1; unsigned int j = 10; if (i < j) printf("1\n"); else printf("2\n"); prints 2, not 1. This is because in i < j , i is converted to an

I want to pass two matrices as argument. These matrices have different size and i don't understand how i have to do this work: #include <stdio.h> #include <stdlib.h> void f(int m[3][], int n); int main() { int A[3][3]={{1,2,3},{4,5, 6},{7,8,9}}; int B[3][2]={{1,2},{3, 4}, {5, 6}}; f(A, 3); f(B, 2); return 0; } void f(int m[3][], int n) { int i,j; for(i=0;i<3;i++) { for(j=0;j<n;j++) printf("%5d", m[i][j]); } return; } How can I do this? The only safe way that I know of to do this is to include the matrix dimensions in the parameters, or make some kind of matrix struct Option A) dimensions as

After reading the chapter about structures in the K&R book I decided to make some tests to understand them better, so I wrote this piece of code: #include <stdio.h> #include <string.h> struct test func(char *c); struct test { int i ; int j ; char x[20]; }; main(void) { char c[20]; struct {int i ; int j ; char x[20];} a = {5 , 7 , "someString"} , b; c = func("Another string").x; printf("%s\n" , c); } struct test func(char *c) { struct test temp; strcpy(temp.x , c); return temp; } My question is: why is c = func("Another string").x; working (I know that it's illegal, but why is it working)? At

I just read: C Wikipedia entry . As far as I know there are 3 different versions of C that are widely used: C89, C99 and C11. My question concerns the compatibility of source code of different versions. Suppose I am going to write a program (in C11 since it is the latest version) and import a library written in C89. Are these two versions going to work together properly when compiling all files according to the C11 specification? Question 1 : Are the newer versions of C i.e. C99, C11 supersets of older C versions? By superset I mean, that old code will compile without errors and the same