Fix: add a check for gnuplot in Makefile

[Urbaner3]

urbaner@urbaner-laptop:~/Documents/linux2026/Modified-Merge-Sort$ make run
Benchmark 10 %
Benchmark 20 %
Benchmark 30 %
Benchmark 40 %
Benchmark 50 %
Benchmark 60 %
Benchmark 70 %
Benchmark 80 %
Benchmark 90 %
Benchmark 100%
make: gnuplot: No such file or directory
make: *** [Makefile:14: run] Error 127

Tested your sort simulation and it fails for missing gnuplot program. So I fix it in makefile.
Here is the patch.

6,8d5
< # Check if gnuplot is available
< HAS_GNUPLOT := $(shell command -v gnuplot 2>/dev/null)
< 
17d13
< ifdef HAS_GNUPLOT
19,21d14
< else
< 	@echo "Warning: gnuplot not found. Skipping plot generation."
< endif
28d20
< 
30,36c22
< ifdef HAS_GNUPLOT
< 	@gnuplot ./scripts/plot.gp
< else
< 	@echo "Error: gnuplot not found. Please install gnuplot to generate plots."
< 	@exit 1
< endif
< 
---
> 	gnuplot ./scripts/plot.gp
39c25
< 	@perf stat ./interval
---
> 	perf stat ./interval
43,44c29
< 	@perf stat ./head_tail
< 
---
> 	perf stat ./head_tail
47c32
< 	@perf stat ./recursive
---
> 	perf stat ./recursive
53d37
< ifdef HAS_GNUPLOT
55,61c39
< 	@gnuplot rand_addr.gp
< else
< 	@echo "Warning: gnuplot not found. Skipping plot generation."
< endif
< 
< .PHONY: build build_example run example clean plot interval head_tail recursive addr
< 
---
> 	@gnuplot rand_addr.gp

Modified Makefile nMake

nMake.txt