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Programming and Data Structures · Recursion
Official IIT answer key · IIT Kanpur · Audited Aug 2026
GATE CSE 2015 Set 2 Q15 · MCQ · 1 mark
void foo(char *a){
if ( *a && *a != ' '){
foo(a+1);
putchar(*a);
}
}
The output of the above function on input "ABCD EFGH" isKey concept
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Topic notes
GATE tests Recursion primarily through direct execution tracing of recursive C code snippets, stack-unwinding behavior (pre-order vs. post-order execution), and termination/infinite recursion analysis. Questions frequently incorporate static variables, pointer/reference aliasing, mutual recursion, and tree/array traversals to test whether candidates can systematically maintain call frames. In recent years, the focus has expanded from standard tracing to higher-order mathematical characterizations (e.g., finding the smallest input or maximum output value of composed recurrences).
Full Recursion guide →Consider the following function written in the C programming language. void foo(char *a) if ( *a && *a != ' ') foo(a+1); putchar(*a); The output of the above function on input "ABCD EFGH" is
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