A named container that holds a value in a program. It is declared with a type such as integer or real and changed by assignment. Assigning a new value discards the previous one.
Japanese name: 変数
Variable appears in 70 practice questions across 11 topics, including Programming Basics (Pseudocode Tracing), Linkers, Loaders & Executables, Multicore & Synchronization.
Answer: C. Register reuse or removed computations left no value
Optimization keeps variables in registers rather than memory and reuses those registers once a value is no longer needed, and constant propagation may remove computations entirely. So when the debugger stops, a variable's value may no longer exist anywhere, and it is shown as "optimized out" or similar. When debugging, it is common to reduce optimization or use a debug-oriented optimization level. Debuggers can still load optimized programs.
Answer: A. .data (initialized data)
Global and static variables with a non-zero initial value go in the .data section, and their initial values are stored in the file. When the program is loaded, this content is copied into memory as is, so limit is already 100 when main starts. Because .data is modified at run time, it is mapped readable and writable.
Optimization keeps variables in registers rather than memory and reuses those registers once a value is no longer needed, and constant propagation may remove computations entirely.
When debugging a program compiled with optimization, some v…Global and static variables with a non-zero initial value go in the .data section, and their initial values are stored in the file.
In C, a global variable written outside any function as "in…A local variable is created in the stack frame when the function is called (optimization may keep it only in a register) and disappears when the function returns.
Where is a non-static local (automatic) variable declared i…Global and static variables live in .bss, which is zero-filled when the program starts, so they begin at 0.
In C, what is true of the starting values of a local variab…volatile tells the compiler not to omit or merge reads and writes of a variable; it was designed for accessing hardware registers.
In C, why is marking a flag variable shared between threads…As an Amazon Associate I earn from qualifying purchases.
Stack Argument Array Pointer Modulo operation Recursion Linker volatile (type qualifier) Microcontroller (MCU) Heap memory