Functions Questions

In C, what does this recursive function return for the input 123, and why is the result printed twice? #include<stdio.h> int sumdig(int); int main() { int a, b; a = sumdig(123); b = sumdig(123); printf("%d, %d ", a, b); return 0; } int sumdig(int n) { int s, d; if(n!=0) { d = n%10; n = n/10; s = d+sumdig(n); } else return 0; return s; }

In C, what will this program print? Note the comma operator in the function and the space in printf. #include<stdio.h> int addmult(int ii, int jj) { int kk, ll; kk = ii + jj; ll = ii * jj; return (kk, ll); } int main() { int i=3, j=4, k, l; k = addmult(i, j); l = addmult(i, j); printf("%d %d ", k, l); return 0; }

In C pointer arithmetic on arrays: what is printed when the function advances a char* pointer over an initialized array? #include<stdio.h> int main() { void fun(char*); char a[100]; a[0] = 'A'; a[1] = 'B'; a[2] = 'C'; a[3] = 'D'; fun(&a[0]); return 0; } void fun(char *a) { a++; printf("%c", a); a++; printf("%c", a); }

In C, function pointers and predicates: what does this program print when comparing equal integers? #include<stdio.h> int fun(int, int); typedef int (*pf) (int, int); int proc(pf, int, int); int main() { printf("%d ", proc(fun, 6, 6)); return 0; } int fun(int a, int b) { return (a==b); } int proc(pf p, int a, int b) { return ((*p)(a, b)); }

In C, trace control flow with a global controlling a while loop and a recursive call to main(). What is printed? #include<stdio.h> int i; int fun(); int main() { while(i) { fun(); main(); } printf("Hello "); return 0; } int fun() { printf("Hi"); }

In C, analyze recursion via calling main() from main() and a toggled local variable. What is printed? #include<stdio.h> int main() { int i=1; if(!i) printf("CuriousTab,"); else { i=0; printf("C-Program"); main(); } return 0; }

In C, passing main as a function pointer: what is the program output order? #include<stdio.h> int fun(int(*)()); int main() { fun(main); printf("Hi "); return 0; } int fun(int (*p)()) { printf("Hello "); return 0; }

In C function-call nesting and assignment evaluation, what will this program print? #include<stdio.h> int fun(int i) { i++; return i; } int main() { int fun(int); int i = 3; fun(i = fun(fun(i))); printf("%d ", i); return 0; }

In C, evaluate nested assignments and function calls: what does this program print for k? #include<stdio.h> int func1(int); int main() { int k = 35; k = func1(k = func1(k = func1(k))); printf("k=%d ", k); return 0; } int func1(int k) { k++; return k; }

On a 16-bit Turbo C (DOS) platform using compiler registers, what will this program print? #include<stdio.h> int main() { int fun(); int i; i = fun(); printf("%d ", i); return 0; } int fun() { _AX = 1990; // set return register (Turbo C extension) for int }

In C, passing by address and modifying in-place: what does this program print? #include<stdio.h> void fun(int*, int*); int main() { int i = 5, j = 2; fun(&i, &j); printf("%d, %d", i, j); return 0; } void fun(int *i, int *j) { *i = *i * *i; *j = *j * *j; }

Post-increment in a return and pre-decrement in printf: what is printed? #include<stdio.h> int main() { int fun(int); int i = fun(10); printf("%d ", --i); return 0; } int fun(int i) { return (i++); }

Recursion with post-decremented actual argument: what does this program do? #include<stdio.h> int reverse(int); int main() { int no = 5; reverse(no); return 0; } int reverse(int no) { if (no == 0) return 0; else printf("%d,", no); reverse(no--); }

Type conversions with nested calls and assignment to a float: what prints? #include<stdio.h> int fun(int); int main() { float k = 3; fun(k = fun(fun(k))); printf("%f ", k); return 0; } int fun(int i) { i++; return i; }

Recursion with pre-decrement on both sides of a print: what is the output sequence? #include<stdio.h> void fun(int); typedef int (*pf)(int, int); int proc(pf, int, int); // (not used) int main() { int a = 3; fun(a); return 0; } void fun(int n) { if (n > 0) { fun(--n); printf("%d,", n); fun(--n); } }

Diagnose the conditional expression and returns: what does this program do? #include<stdio.h> int check (int, int); int main() { int c; c = check(10, 20); printf("c=%d ", c); return 0; } int check(int i, int j) { int *p, *q; p = &i; q = &j; i >= 45 ? return(*p) : return(*q); }

Simple conditional return in C: given i=45, what does this program print? #include<stdio.h> int check(int); int main() { int i = 45, c; c = check(i); printf("%d ", c); return 0; } int check(int ch) { if (ch >= 45) return 100; else return 10; }

In C programming, what will be the actual output of this program (consider control flow and the call to exit): #include<stdio.h> #include<stdlib.h> int main() { int i = 0; i++; if (i <= 5) { printf("CuriousTab"); exit(1); main(); } return 0; } Choose the exact behavior/output.

C language semantics: “In C, all functions except main() can be called recursively.” Decide whether this statement is correct or incorrect.

C return semantics: “Functions cannot return more than one value at a time.” Decide whether this statement is correct or incorrect.